339. Logic
A. MS., notebook, n.p., November 12, 1865-November 1, 1909.
CSP kept this notebook from 1865 until his death, recording in it (and dating) many of his investigations in their first stages: "Here I write but never after read what I have written for what I write is done in the process of forming a conception." The sheets have been ordered and numbered by Professor Don Roberts, and a page by page index has been provided by him and is kept with the notebook. Among the topics included are: real definition, the categorical syllogism, intension and extension, the logic of relatives, existential graphs, collections, the theory of signs, induction and hypothesis, the history of science, scepticism and common sense, the nature of truth, liberty and necessity.


It is not certain that all the lectures listed below belong to the University Lecture Series or that the order in which they are noted in the catalogue is the order in which they were actually given in the spring of 1865. For instance, MS. 343 duplicates, without mentioning it, the content of 342. It is conceivable that MS. 343 is Lecture V of the 351 series. Again, MS. 345 and MS. 356 begin in the same way. It is conceivable that MS. 345 is a later draft of MS. 356.

340. Lecture I
A. MS., n.p., [1864-65], pp. 1-2, 4-10 of one draft; p. 4 of another draft (all are double pages).
Preface on the reforms of science, including reform in logic. Plan of the lectures.

341. Lecture II
A. MS., n.p., [1864-65], pp. 1-12 (double pages).
Problem of induction: logical or extra-logical? The answer as suggested by Aristotle's views on induction. Distinction between premises and conclusions, and between data and inference. No induction by simple enumeration. A posteriori reasoning distinguished from deduction and induction. The three figures of a priori inference; the three principles of inference a posteriori. For an earlier draft of the first page, see MS. 765.

342. Lecture III
A. MS., n.p., [1864-65], 33 pp.
Theories of probabilities (Doctrine of Chances). Most of the lecture, however, concerns some peculiarities of Boole's algebra. Brief discussions of the history of logic and some sophism.

343. Lecture V
A. MS., n.p., [1864-65], 36 pp.
The two kinds of scientific inference induction and hypothesis differ from the syllogistic inference as much as they do from each other. Nevertheless, the three coordinate classes of reasoning are deduction, induction, and hypothesis.

344. Lecture VI. Boole's Calculus of Logic (Boole)
A. MS., n.p., [1865-66], pp. 1-10, 11-14 (mostly double pages).
Boole's work marks an epoch in the history of logic "which in point of fruitfulness will rival that of Aristotle's Organon."

345. Lecture VII
A. MS., n.p., [1864-65], 34 pp., with 2 pp. of another start.
This lecture begins the second half of the lecture series. The definition of "logic." Kinds of logical systems. All deductive reasoning is merely explicatory. Direct and indirect implication. What a word denotes and what it connotes. The sphere and the content of a word. Extension and comprehension. Being (all breadth, no depth) and Nothing (all depth, no breadth). Modification of the law of the inverse proportionality of extension and comprehension. The information of a term. On the subject of induction and hypothesis, CSP writes of the slight preponderance of true over false scientific inferences, and he finds that the reason for this is the vague tendency for the whole to be like any of its parts, taken at random.

346. Lecture VIII. Forms of Induction and Hypothesis (Forms)
A. MS., n.p., [1864-65], pp. 1-14 (double pages).
The attempts to define "logic" suffer from an admixture of logic, anthropology, and psychology. Analysis of the triad of thing, representation, and form. The three kinds of representations: signs, copies, symbols. Conditions to which symbols are subject. The relationship between the syllogism and scientific inference. The proper form of induction. Induction and hypothesis distinguished. Induction increases the extension of subject; hypothesis increases the comprehension of predicate. Moreover, induction discovers a law which is a prohibition; hypothesis discovers a law which is an imposition.

347. Lecture X. Grounds of Induction (Grounds)
A. MS., n.p., [1864-65], 15 double pp. (with one double p. missing); plus pp. 1-4, incomplete, entitled "Lecture on the Grounds of Inference." Kinds of propositions: denotative, informative, connotative. Relationship of denotative, informative, connotative propositions to propositions which are simple, enumerative, and conjunctive. The peculiarities of the latter. The three kinds of inference and their ground.

348. Lecture XI (XI)
A. MS., n.p., [1864-65], pp. 1-16 (double pages).
Long recapitulation of the previous lecture. What is the probability that an induction or hypothesis is true? CSP concludes that the question is senseless both from the viewpoint of the nature of propositions and the nature of logic. Sundry comments on the views of Sir William Hamilton.

* 348a. (Bacon)
A. MS., n.p., n.d., p. 7 and 1 p.
A lecture on Bacon was promised (see MS. 340). But only two pages which may be part of that lecture have been found.

349. Lecture on Kant (Kant)
A. MS., n.p., [1864-65], pp. 1-14, with all but p. 12 being double pages.
Presumably the 12th lecture of the University Lecture Series. "Every man who wishes to vindicate his pretensions to philosophic power must display it by the discovery of an error in Kant." Most usually the critics of Kant have simply misunderstood him. Examples of misunderstanding provided. A preliminary study of Kant's Critique of Pure Reason, treating such topics as the A Priori, The Transcendental Esthetic (the objective validity of the representations of space and time), Kant on the nature of judgment.

350. Lecture on the Theories of Whewell, Mill, and Compte (Whewell)
A. MS, n.p., [1864-65], pp. 1-14 (double pages).
Presumably part of the University Lecture Series. There is a note that another lecture on Waddington, De Remusat, Graty, and others was to follow this one. Several modern theories of science treated as inseparable from the metaphysics of their authors. For example, Whewell is a Kantian. Comte is "helplessly restricted to a simple intellectual view." Critisism of Mill's logic, especially Mill's views on the ground of induction.


351. Lecture I
A. MS., n.p., October 24, 1866, 39 pp.
The bad reputation of logic, with its endless controversies between realism and nominalism. Among modern logicians, CSP distinguishes the formal and the anthropological logicians. Logic as a classificatory science. The traditional syllogism, with a note that the second lecture would be concerned with the hypothetical syllogism.

352. Lecture I
A. MS., n.p., 1866, 29 pp.
The nature of logic. Kinds of arguments. The moods and figures of the categorical syllogism.

353. Lecture II
A. MS., n.p., October 27, 1866, 30 pp.
Continues MS. 351. On the hypothetical syllogism. Included here is a discussion of Zeno's paradoxes as well as a discussion of several sophisms.

354. Lecture III
A. MS., n.p., October 31, 1866, 31 pp.
Probability. Meaning of "likely" and "probable." Boole's algebra. What is the justification of induction? What are the common characters of inference in general? CSP records and then criticises answers commonly given to these questions by mathematicians and theologians.

* 355. Lecture IV
A. MS., G-1866-2a, November 3, 1866, 34 pp. (numbered by an editor).
Published, in part, as 7.131-138 (pp. 27-32). Unpublished is the recapitulation of previous lecture and J. S. Mill's answer to the question of induction along with CSP's criticism of that answer, especially Mill's notion of the uniformity of nature.

356. Lecture VII
A. MS., n.p., delivered November 14, 1866, 6 pp.
This lecture begins the second half of the lecture series. Extention and comprehension. Digression on the intellectual superiority of Boston (CSP is pleased by the hearing he has received during the first six lectures, especially, as he says, on a subject as dry as logic). Role of philosophy in America: A promise of things to come, but as yet there is no American philosophy. Notes several traits in the Yankee character which are conducive to philosophizing.

357. Lecture IX
A. MS., n.p., [1866], 28 pp. and 8 pp. of different drafts; plus a quotation from Herbart.
First sense impressions are not representations of unknown things but those things themselves. Sensation and conception as representations. Universal conceptions: Substance and Being, with the intervening conceptions of Ground, Correlate, and Interpretant. Quality, relation, and representation. The three kinds of representations. Icon, index, and symbol. Division of symbol into term, proposition, and argument. Kinds of terms. Hamilton's views considered. The classification of the sciences.

* 358. Lecture X
A. MS., n.p., [1866-67], 3 pp. (fragmentary).
All cognition is inferred from some other cognition, i.e., there is no first premise or intuition. Some consequences of this view.

359. Lecture XI
A. MS., G-1866-2a, 29 pp. (page numbers supplied by an editor).
Published, in part, as 7.579-596 (pp. 1-22, with a single deletion). Unpublished (pp. 22-29): Symbols and the trinity of object, interpretant, and ground. Agreement between this trinity and the Christian Trinity. The interpretant is the Divine Logos. "If our former guess that a Reference to an interpretant is Paternity be right, this would also be the Son of God." The ground corresponds in its function to the Holy Spirit. A discussion of philosophical tendencies in children terminates with the conclusion that the peculiar differences of men are philosophical differences.


360. Chapter I
A. MS., G-c.1873-1, 3 pp. of fragments.
7.315, 7.315n5, and 7.316 are from these pages.

361. Chapter I (Enlarged Abstract)
A. MS., G-c.1873-1, 2 pp.
Published in entirety: 7.313-314.

362. Chapter I (Enlarge Abstract)
A. MS., n. p., [c.1873], 1 p.

363. [Fragment]
A. MS., G-c.1873-1, 1 p.
Published, in part: 7.314n4.

364. Logic. Chapter 2. Of Inquiry
A. MS., G-c.1873-1, 1 p., incomplete; plus 9 pp. of another draft and 5 loose sheets.
Only the draft of 9 pp. was published: 7.317-325.

365. Chapter 2
A. MS., n.p., [c.1873], pp. 1, 4.
The end or purpose of inquiry is to close inquiry; its end is not its own exercise. The spirit of disputatiousness is best promoted by practical applications of reason.

366. Logic. Chapter 3. Four Methods of Settling Opinion
A. MS., n.p., [c.1873], p. 1, incomplete.

367. Logic. Chap. 4. Of Reality
Amanuensis, corrections in CSP's hand, G-c.1873-1, pp. 1-23.
Published, in part as 7.327-335 (pp. 1-17) Unpublished: reality and the final opinion upon which men are destined to agree. Reality is that thought with which we struggle to have our thoughts coincide. It can mean nothing at all to say that, in addition, some other reality exists.

368. Chapt. 4 (2nd Draft)
Amanuensis, corrections in CSP's hand, n.p., [c.1873], pp. 1-7.
Thought is regarded as a stream governed by the law of association. Independent reality is placed either at the beginning or the end of the stream. The law of association cannot account for the coherence and harmony of experience. Distinction between dreams and external experience.

369. Logic. Chap 4 ( ____ draft)
Amanuensis, G-c.1873-1, pp. 1-6.
Published, in part, as 7.326 (pp. 1-3). Unpublished: reflections on feeling. The relationship of feeling to other feelings is such that, apart from succession in time, there are no relationships. Every feeling in itself is unanalyzable and absolutely simple.

370. [Chapter 4. Of Reality]
Amanuensis, G-c.1873-1, 11 pp.
Published in entirety: 7.336-345.

371. Logic. Chapter IV. Of Reality
A. MS., n.p., [c.1873], 18 pp. of fragments.
Investigation consists of two parts: reasoning and observation. The confusion between thought as an operation of thinking and thought as an object. Belief and the habitual connection of ideas, with belief and habit of thought being one and same thing. Fixation of belief. No genuine doubt attaches to the scientific method of fixing belief, just as no genuine doubt can attach to the belief in real things.

372. Logic. Chapter IV. Of Reality
A. MS., n.p., [c.1873], 14 pp.
Investigation involves both observation and reasoning. Reasoning as beginning with the most obvious premises and leading ultimately to one conclusion. Reality must be connected with this chain of reasoning at one extremity or the other. Nominalistic and realistic views of reality. The scientific presentation of the doctrines of logic requires the identity of the object of true knowledge with reality. The existence of things (as studied by physicists) depends upon their manifestability. Extending this conception to all real existence leads to an idealistic theory of metaphysics, once it is clearly understood that observation and reasoning are perpetually leading us toward certain final opinions whose objects may be said to have real existence.

373. Of Reality
A. MS., G-c.1873-1, pp. 1-20.
Published, in part, as 7.331n9 (p. 2) and 7.313n3 (pp. 8-9). Unpublished: investigation as involving both observation and inference, and ultimately the agreement of all investigators. How the conception of mind is acquired. Refutation of the claim that no distinction can be drawn between knowing and knowing that one knows. Does the mind have a direct experience of its own existence from the moment it is first conscious of anything? Signs and cognitions.

374. On Reality A. MS., n.p., [c.1873], 4 pp.
What is the meaning of reality? To answer this question requires an answer to the question of meaning in general. As a start CSP asks whether a feeling can be said to have meaning. An analysis of feeling reveals its complexity.

375. On Reality
A. MS., n.p., [c.1873], 1 p.
The notion of nothing. Absurdity and unreality are two distinct cases of nothing.

376. [Time and Thought]
Amanuensis, G-c.1873-1, March 6, 1873, pp. 1-9.
Published in entirety: 7.346-353.

377. [Time and Thought]
Amanuensis, n.p., March 8, 1873, pp. 1-9.
Temporal succession of ideas as continuous. Definition of "continuum" as "something any part of which itself has parts of the same kind." Cf. MS. 376.

378. Logic. Chap. 5th
Amanuensis, G-c.1873-1, March 10, [1873], 6 pp.
Published in entirety: 7.354-357.

379. Logic. Chap. 6th
Amanuensis, G-c.1873-1, March 10, 1873, pp. 1-10; plus an exact copy (pp. 1-8) in another hand [Zina Fay Peirce?].
Published (pp. 5-6) as 7.336n Omitted from publication: the three elements of signs. The nature of the causal connection between a thought and the thing to which it is related. Reality and figment: Reality is the most general of expressions (even a figment is a reality when considered in itself and not as the representation of something else). What is real or what exists must be an object of thought, because it is impossible to have a conception of anything which is not an object of thought. That is, the attempt to discover a word which expresses a thing that exists without, at the same time, implying that that thing is a possible object of thought results in a contradictory (or meaningless) expression.

380. Logic. Chap. 7. Of Logic as a Study of Signs
Amanuensis, n.p., March 14, 1873, 4 pp.
The three conditions for the existence of a sign.

381. On the Nature of Signs
Amanuensis, n.p., 6 pp. and 7 pp. of two drafts.
The six-page manuscript: the three conditions for the existence of a sign The seven-page manuscript: Kant's Categories of the Understanding; Medieval logic and the division of conceptions into first and second intentions; the threefold division of representation and terms.

382. Logic. Chap. 9th
Amanuensis, n.p., March 15, 1873, 12 pp.
Ambiguity and indeterminacy. Principles of formal logic. Equiparence of the copula.

383. Chap. X. The Copula and Simple Syllogism
Amanuensis, n.p., [C.1873], 6 pp.
All reasoning is reducible to syllogistic form and is dependent upon the transitive character of the copula. Formal properties of the copula.

384. Chap. XI. On Logical Breadth and Depth
Amanuensis, n.p., [C1873], 9 pp.
First and second intentions. "Breadth" and "depth" defined. Also defined "informed breadth" and "informed depth." A distinction is made between essential and substantial breadth and depth.

385. Logic Chapter. The List of Categories
A. MS., n.p., [C.1873], 2 pp.
Reality and Being distinguished. Doubt involves something fixed and something vague. The thing about which we doubt is fixed; what is in doubt about the thing is vague.

386. Chap. VIII. Of the Copula
A. MS., n.p., [c.1873], 3 pp., plus another page with the same title.
The properties of the copula summarized.

387. Chap. IX. Of Relative Terms
A. MS., n.p., [c.1873], 8 pp.
A study of the properties of individuals, i.e., the properties individuals would possess if they existed. General relative terms. Logic as the science of identity.

388. On Representations
A. MS., n.p., [c.1873], 3 pp.
"Representation" defined. The three things essential for having representation.

389. On Representation
Amanuensis, corrected by CSP, n.p., [c.1873], 10 pp.
The three things which are essential for representation: Representation must have qualities independent of its meaning, it must have real causal connection to its object, and it must address itself to some mind.

390. Chapter IV. The Conception of Time essential in Logic
A. MS., n.p., July 1, 1873, 4 pp.
The conception of a logical mind presupposes a temporal sequence among ideas, for every mind which passes from doubt to belief involves ideas which follow one another in time. The flow of time is not by discrete steps, but is continuous. "Continuum" defined.

391. Chapter IV. The Conception of Time essential in Logic
A. MS., n.p., July 2, 1873, 8 pp.
MS. 391 is an expanded version of MS. 390.

392. Chapter V. That the significance of thought lies in its reference to the future
A. MS., G-c.1873-1, 4 pp.
Published in entirety: 7.358-361.

393. (Pract. Logic, Lect. Logic)
A. MS., n.p., n.d., 3 pp.
Opinions tend toward ultimate settlement. The proposition that there is some reality which determines opinions but does not depend upon them admits of two interpretations, but on either interpretation, the real is ideal. Reality and actualities.

394. Memorandum. Probable Subjects to be Treated of
Amanuensis, n.p., n.d., 1 p.

395. Third Lecture
A. MS., n.p., n.d., 2 pp.
The question, What is thought? can only be answered by means of thought.

396. [Fragments]
A. MS., n.p., n.d., 13 pp.
Among the topics treated here are the following: relative and absolute terms; negation; the syllogism; cognition and inconceivability; thought and signs; feelings, the continuum of feelings, and time.

("How to Reason: A Critick of Arguments")

*397. How to Reason: A Critick of Arguments. Advertisement
A. MS., G-1893-5, pp. 1-12.
Only the 1st paragraph of p. 1 was published: Collected Papers, Vol. 8, p. 278. Unpublished: a general summary of CSP's work in philosophy and logic, along with a short account of the significance of his efforts in logic, and a discussion of continuity as ubiquitous mediation.

398. [How to Reason: A Critick of Arguments. Advertisement]
A. MS., G-1893-5, pp. 1-11.
Only the last 4 paragraphs (pp. 10-11) published: Collected Papers, Vol. 8, pp. 278-279. Unpublished: a summary of CSP's work in philosophy and logic which is more detailed than the one found in MS. 397. Other subjects dealt with but not published are the analysis of propositions, the statistical syllogism, the conception of quantity and continuity, and the realism-nominalism issue.

399. How to Reason: A Critick of Arguments. Contents
A. MS., G-1893-5, pp. 1-3, with variants.
Pages 2-3 published: Collected Papers, Vol. 8, pp. 279-280. Only the title page was omitted.

400. Book I. Of Reasoning in General. Introduction. The Association of Ideas
A. MS., G-1893-5, pp. 9-83, 17-19; plus two drafts (5 pp.) of "contents."
Published in part as 7.388-450, except 392n7. Unpublished: pp. 14-51, with exception of proposition 3 on p. 23 which was published as 7.417n21. History of the doctrine of association which begins with Aristotle and continues with the English writers of the seventeenth and eighteenth centuries, e.g., Digby, Locke, Hume, Hartley, Gay, among others, and the nineteenth-century English, German, and American thinkers, e.g., James Mill, Hamilton, Bain, Lewes, James, Herbart, Wundt. "Notwithstanding the writer's realism and realistic idealism, and consequent high appreciation of Schelling, Hegel, and others, and respect for German industry, he cannot but regard the English work in philosophy as far more valuable and English logic as infinitely sounder."

401. Book I. Logic in General. Introduction. The Association of Ideas
A. MS., n.p., 1893, pp. 9-11, incomplete.

402. The Association of Ideas
A. MS., n.p., 1893, pp. 2-13, with p. 3 missing.
The Principles of Association: the general rules in accordance with which one idea has a tendency to suggest another. Page 11 begins a Chapter II, which sets out to deal with the problem of time, memory, and experience.

403. Division I. Formal Study of General Logic. Chapter I. The Categories
A. MS., n.p., 1893, pp. 16-29.
Association of ideas. Process of unification (the blending and spreading of ideas). Distinguishable grades in the process of unification. The conception of the present. Being and substance. The passage from being to substance is mediated by accident, whose threefold nature includes quality, relation, and representation. Quality is Firstness; relation, Secondness; representation, Thirdness. Primary qualities and feelings. Phenomenalism and the relativity of knowledge. The two great genera of relations: those whose ground is prescindible and those whose ground is not. Precision, or abstraction, distin-guished from other modes of mental separation, e.g., discrimination and dissociation. Compare with "On a New List of Categories" [PAAAS series on logic (1867)]. See G-1867-1a.

404. The Art of Reasoning. Chapter II. What is a Sign?
A. MS., G-1893-5, pp. 31-46 (pp. 34, 42 missing).
Published, in part, as 2.281 (pp. 35-36), 2.285 (p. 41), 2.297-302 (pp. 43-45). Unpublished: reasoning as an interpretation of signs of some kind; the three different states of mind feeling, reacting, thinking (pp. 31-34). Indices and icons (pp. 37-40). Reasoning as requiring a mixture of likenesses, indices, and symbols (p. 46).

405. Division II. Transcendental Logic. Chapter III. The Materialistic Aspect of Reasoning
A. MS., G-1893-5, pp. 47-54.
Published in entirety as 6.278-286.

406. Chapter IV. What is the Use of Consciousness?
A. MS., G-1893-5, pp. 55-58.
Published in entirety as 7.559-564.

407. Chapter V. The Fixation of Belief
A. MS. (and TS.), n.p., 1893, pp. 59-84; plus 1 p. ("Chapter IV. The Fixation of Belief").
A version of the article bearing the same title first published in the Popular Science Monthly (1877), as the first in a series of articles appearing under the general title "Illustrations of the Logic of Science." The original article of 1877 was published in the Collected Papers as 5.358-387, except 358n*, with revisions and notes of 1893, 1903, and c.1910. See G-1877-5a.

408. Division III. Substantial Study of Logic Chapter VI. The Essence of Reasoning
A. MS., G-1893-5, pp. 85-180 (p. 163 missing) and a variant p. 85.
Published, in part, in two places: 4.21-52 (pp. 89-146, with deletions) and 7.463-467 (pp. 168-173). Unpublished: the early history and literature of logic (pp. 85-88). Experience, reality, and belief-habits; the inner and outer world of man's experience; the law of association and its principles (pp. 147-165).

409. Division III. Substantial Study of Logic. Chapter VI. The Essence of Reasoning
A. MS., G-1893-5, pp. 85-141 (pp. sog, 130 missing), with 8 pp. of variants.
Published, in part, as 4.53-56 (but not all of 56) and 4.61-79 (pp. 91-141, with deletions). The unpublished pages concern terminology mainly: term, concept, proposition, judgment, argument, and the operation of naming. As an aside, CSP's low opinion of the logical powers of the Germans.

410. Book II. Introductory. Chapter VII. Analysis of Propositions
A. MS., n.p., 1893, pp. 1-18; 1-19 (of a secretary's inaccurate copy).
Why should one want to reason? Reason versus instinct. Reasoning well requires an understanding of the theory of reasoning. The vocabulary of logic. Categorical and hypothetical propositions. "Every mother loves some child of hers" represented graphically. Nominalism and realism. Conjunctives.

411. Division I. Stecheology. Part I. Non Relative. Chapter VIII. The Algebra of the Copula
A. MS., n.p., 1893, pp. 171-234.
Material Implication. CSP introduces a new symbol -| for the (his) symbol -<. All algebra based on simple definition of -|. On the infinite series of logical terms (logically necessary consequences). Five types of logical propositions. The crocodile paradox (dilemmatic reasoning). CSP regards logical algebra as important as an instrument for logical analysis, but of no great importance as calculus. Rules of logical aggregation and composition.

412. Division I. Stecheology. Part I. Non Relative. Chapter VIII. The Algebra of the Copula
Amanuensis, n.p.. 1893, pp. 20-84.
Second draft of MS. 411, but with no substantial changes.

413. Chapter IX. The Aristotelian Syllogistic
A. MS., G-1893-5, pp. 211-285.
Published, in part, as 2.445-460 (pp. 211-232, with deletions). Unpublished are CSP's comments on the contributions to philosophy of Hamilton, Kant, DeMorgan, and Aristotle as logicians. Importance of the syllogism, especially of the figures, in probable inference. The reduction of syllogistic forms. Natural classification of the moods. Formal fallacies, e.g., ignoratio elenchi and petitio principii. Semi-material fallacies, e.g., fallacies of ambiguity and erroneous particularization.

414. Chapter X. Extension of the Aristotelian Syllogistic
A. MS., G-1893-5, pp. 286-296.
Published as 2.532-535 with only the quotations from Hamilton on pp. 291-293 deleted.

415. De Morgan's Propositional Scheme
A. MS., n.p., 1893, pp. 297-313.
CSP improves upon De Morgan's system by expanding it and giving it graphical representation. De Morgan's views on modal logic and Christine Ladd-Franklin's scheme (from Studies in Logic, by Members of the Johns Hopkins University) examined. Also examined are Gilman's views on spurious propositions.

416. On a Limited Universe of Marks
A. MS., G-1893-5 and G-1883-7c, pp. 314-325.
This manuscript is a rewritten version of one of CSP's contributions (Note A: "Extension of the Aristotelian Syllogistic") to Studies in Logic, By Members of the Johns Hopkins University (edited by C. S. Peirce), 1883. What was published (2.517-531) is the 1883 "note," as rewritten in 1893 for Chapter X of the Grand Logic. The difference between the two papers is not substantial.

417. Chapter XI. The Boolian Calculus
A. MS., n.p., 1893, pp. 326-349.
Defense of "or" as allowing for "and." Definition of material implication. Examples from Mrs. Ladd-Franklin (in Studies in Logic). Compare with "On the Algebra of Logic: A Contribution to the Philosophy of Notation"
(G- 1885-3) .

418. Book II. Division I. Part 2. Logic of Relatives. Chapter XII. The Algebra of Relatives
A. MS., n.p., 1893, pp. 350-372.
"If I have made any substantial improvement in logic, it is in the discovery of this manner of dealing with the imperfections of Boolians." Exhibiting and remedying imperfections of the Boolean calculus. Logic of relations, which, CSP says, he brought to essential completion in 1885 (G-1885-3). First and second intentional logic. Machines which are capable of solving problems in non-relative Boolean algebra, with an examination of the performance of one of them (Allan Marquand's, as reported in the Proceedings of the American Academy of Arts and Sciences, XXI. 303).

419. Chapter XIII. Simplification for Dual Relatives
A. MS., G-1893-5 and G-1883-7d, pp. 373-389, with a note that p. 376 was "struck out."
This manuscript is substantially the same as one of the contributions (Note B: "The Logic of Relatives") to the Johns Hopkins Studies in Logic. What was published (3-328-358) is the 1883 "note," with a marginal note and indications of the revisions of 1893 for the Grand Logic. New symbolism is introduced. Relatives are developed without or .

420. Chapter XIV. Second Intentional Logic
A. MS., G-1893-5, pp. 390-394.
Published in entirety as 4.80-84.

421. Division II. Methodology. Chapter XV. Breadth and Depth
A. MS., G-1893-5 and G-1867-1e, pp. 395-438.
What was published (2.391-426) is "Upon Logical Comprehension and Extension" of Proceedings of the American Academy of Arts and Sciences, Vol. 7, November 3, 1867, with the revisions of c.1870 and 1893. What was published as 2.427-430 is a supplement entitled "Terminology" (G-1893-7). In addition to being Chapter XV of the Grand Logic, this manuscript was also intended as Essay III of the Search for a Method (1893).

* 422. Methodology. The Doctrine of Definition and Division. Chapter XVI. Clearness of Apprehension
TS, G-1893-5 and G-1877-5b, pp. 439-452; A. MS., pp. 453-456, which continues 452 of TS.
What was published as 5.388-410 is the essay "How to Make our Ideas Clear" (Popular Science Monthly, Vol. 12, pp. 286-302, 1878), with the additions of 1893.

423. Book III. Quantitative Logic. Chapter XVII. The Logic of Quantity
A. MS, G-1893-5, pp. 1-124 (pp. 2, 102-103 missing); plus a complete and corrected copy of 125 pp., neither the copy nor the corrections in CSP's hand.
Published, in part, as 4.85-152 (pp. 1-125, with omissions and with a marginal note).
424. Chapter XVIII. The Doctrine of Chances
TS., G-1893-5 and G-1877-5c, pp. 581-591.
What was published as 2.645-660 is the third article of the series "Illustrations of the Logic of Science" (Popular Science Monthly, Vol. 12, pp. 604-15, 1878), with corrections of 1893 and a note of 1910.

Minute Logic 1902-03

425. Minute Logic, Chapter I. Intended Characters of this Treatise (Logic)
A. MS., G-c.1902-2, pp. 1-170, with variants and a typewritten copy which differs only slightly from the original; pp. 1-50, with variants, of an incomplete first draft.
Publication (2.1-118) is from CSP's typewritten copy, with a few omissions consisting of repetitions and asides.

426. Chapter II. Prelogical Notions. Section I. Classification of the Sciences (Logic II)
A. MS., n.p., February 13, 1902, pp. 1-41, with 1l pp. of variants.
An earlier draft of MS. 427.

427. Chapter II. Prelogical Notions. Section I. Classification of the Sciences (Logic II)
A. MS., G-c.1902-2, begun February 20, 1902, pp. 1-291, with nearly 200 pp. Of variants; pp. 97-125, 190-192, 196-197, 244, 271-273 from alternative drafts.
A later draft of MS. 426. Published, in part, as 1.203-283 (pp. 1-123, with omissions), 7.374n10 (pp. 125-127), 7.279 (pp. 140-142), 7.362-363 and 7.366-385 (pp. 192-242). From the alternative drafts, pp. 190-192, 196-197, 271-273 were published as 7.364, 7.365, and 7.386-387 respectively. Omitted from publication are the following: notions of family, genus, species; dynamics as a suborder of Nomological Physics; statics; theories of the constitution of matter and nature; hydrodynamics; dynamics of a particle and of rigid bodies; subfamilies of rigid dynamics; molar, molecular, and ethereal physics; cross-classification; subdivision of special nomological physiognosy; crystallography; "diagrammatic" history of astronomy; minerology; chemistry; the natural metric system; suborders of physiotaxy; families of natural history; genera of biology; physiography; physiognosy; genera and species of astronomy; geognosy. From alternative drafts, the following were omitted: the Genus language; classifications of language; races of mankind and the origin of the white race; resemblances between Polynesian and Semitic languages; the question of a common linguistic ancestor; Basque; agglutinative speech.

428. Chapter II. Section II. Why Study Logic? (Logic II, ii)
A. MS., G-c.1902-2, pp. 1-128, with 33 pp. of variants.
The second page is dated April 28, 1902; the hundred and second page, April 3o, 1902. Published in entirety as 2.119-202.

429. Chapter III. The Simplest Mathematics
TS., for most part, G-c.1902-2, pp. 1-127.
Published as 4.227-323, with historical notes on signs and several theorems in algebra and logic omitted.

430. Chapter III. The Simplest Mathematics (Logic III)
A. MS., n.p., 1902, pp. 2-108 (p. 9 is missing), with many rewritten sections.
Some of the pages of this manuscript are dated; page 4, for instance, is dated January 2, 1902. On postulates (footnote on the corruption of Euclid's text and the confusion between "axioms" and "postulates"). Principles of contradiction and of excluded middle. The development of Boole's logical algebra. Logical depth and breadth. Composition and aggregation: De Morgan and Jevons. Beginning with generals, logic requires notion of inference; its primary aim is criticism of inference. Definition of an "individual." Confusion of collective identity with individual identity. Algebra of the copula of inclu-sion. The meaning of the mathematical "is." Algebraical consequence: constituents of a consequence; standard and potential constituents; proximates of a consequence. Scriptibility. The "vital" definitions of the algebra. Distinction between collective and distributive applicability of a disjunction to "v." The distinction between several and joint applicability to "v." Close
and loose combinations and their denial. Definition of the generalized copula of inclusion in five clauses. Theorems and rules of the algebra. In the alternative sections: existential graphs (pp. 14-68); explanation of CSP's notation for Boolean algebra (pp. 35-45); algebra of the copula, formal definitions of "if," "and," "or," employed in defining ; and more on consequence (pp. 56-76)

431. Chapter III. The Simplest Mathematics (Logic III)
A. MS., n.p., 1902, pp. 2-200 (p. 199 missing), including long alternative or rejected efforts.
Page 37 is dated January 5, 1902; another page, January 28, 1902. Two definitions of "mathematics" analyzed: (a) mathematics as the method of drawing necessary conclusions, and (b) mathematics as the study of the hypothetical states of things. Mathematics does not require ethics; logic does, however. Preliminary dissection of mathematics into several branches. The important rules, theorems, and demonstrations of dichotomic mathematics. Simplest mathematics is a two-valued system, but even though its subject is limited, it does enter as an element into the other parts of mathematics, and hence is important. In regard to trichotomic mathematics, it is asked, "how is the mathematician to take a step without recognizing the duality of truth and falsity?" Fundamental fact about the number three is its generative potency. Philosophical truth has its origin and rationale in mathematics. A chemical analogy. In one of the alternative sections, there is a lengthy account of CSP's dispute with Sylvester over who should receive credit for discovering the system of nonions.

432. Chapter IV. Ethics (Logic IV)
A. MS., n.p., [c.1902], pp. 1-8.
The start of a first draft. Moral virtues required in performing inductions. What constitutes a normative question? Pure ethics philosophical ethics regarded as a pre-normative science but of vital importance to the student of logic. Truth and reality.

433. Chapter IV. Ethics (Logic IV)
A. MS., G-c.1902-2, pp. 1-21.
Published in entirety as 1.575-584.

434. Chapter IV. Ethics (Logic IV)
A. MS., G-1902-2, pp. 12-234 (p. 12 follows the first eleven pages of MS. 433).
Published, in part, as 6.349-352 (pp. 20X-220). Unpublished: long footnote on the term "conscience," leading to eight rules having to do with the ethics of terminology and the governing of philosophical terminology. CSP proposes to list and examine twenty-eight conceptions or classes of supposed goods, e.g., the desirable in itself, but only gets as far as the fifteenth (all were taken from Greek philosophy, with Plato's conception of the ultimate good to have formed the basis of the fifteenth conception). At this point in the manuscript a long digression occurs which continues to the close. The digression concerns disputed points of Plato's life. In this connection, there is considerable material on the chronological order of the Platonic Dialogues as well as on Lutoslawski's researches. Sophistries in the Sophist, but Plato's definition of being as power approved. Various comments on the Politicus and Timaeus. For CSP, Plato's strength lies in his ethics, not in his metaphysics and logic.


435. On Detached Ideas in General, and on Vitally Important Topics as Such (1898)
A. MS., G-1898-1, pp. 1-35.
Lecture I: published as 1.649-677, with omissions. Discourse on admirable and contemptible qualities. The qualities most admired, e.g., devotion and courage, are instinctual; the contemptible qualities derive from reasoning. The origin and influence of the "mechanical philosophy." "But it is one of the great virtues of scientific method that the scientist need not be a deep thinker or even a cultivated mind .... Men of this sort believe in the mechanical philosophy."

436.Lecture I (1898)
A. MS., n.p., 1898, pp. 1-34 (pp. 6-9, X 3, 15-26, 30, 33 missing).
Reason and instinct. The wise man in matters of greatest importance will follow, not his reason, but his heart. Reason and religion. The contention that metaphysics is a guide for the soul is humbug. Moreover, the talent for reasoning is as uncommon as the talent for music, and the cultivation of the first requires a greater effort with fewer immediate rewards. CSP's bitterness is not easily restrained. He advises against philosophy as a career, shows his disdain of Harvard gentlemen and of publishers who refuse to publish treatises on logic on the ground that the author is not a university professor and that the work would not pay for itself.

437. Philosophy and the Conduct of Life (PL)
A. MS., G-1898-1, pp. 1-31.
Lecture I: published, in part, as 1.616-648 (pp. 1-16, 30-31). Unpublished material on the classification of the sciences and on the fact that every science grows into a more abstract science, one step higher on the classificatory scale. Asides on Plato.

438. Detached Ideas on Vitally Important Topics. Lecture II (TVI II)
A. MS., G-1898-1, pp. 1-23, incomplete, with 3 loose sheets (notes for lecture).
Selection published: 4.1-5. Deleted: pp. 1-4, 11-17, 18-22 on the relationship between philosophy and mathematics and between philosophy and the exact sciences, on the gross abuse of the word "realism," on the Peircean categories and the logic of relatives. CSP offers an explanation (suggested by a theorem of the logic of relatives that no polyads higher than triads are required to express all relations) of why his list of categories is complete. Co-discoverer, with De Morgan, of the logic of relatives, CSP introduces the reader to that logic by means of existential graphs.

439. Detached Ideas continued and the Dispute between Nominalists and Realists (NR)
A. MS., n.p., 1898, pp. 1-35, with a variant p. 24.
Peircean categories of Firstness, Secondness, Thirdness. The system of graphs is a consequence of CSP's study of the categories. Logic of relatives and the notion of generality (universality). The continuum as the true universal. Kant on continua. The question of reality. The nominalist-realist controversy. The tendency to think of nature as syllogizing, even on the part of the mechanist. But nature also makes inductions and retroductions. Infinite variety of nature testifies to her originality (or power of retroduction). That continuity is real and the significance of this fact for a philosophy of life. CSP's extreme realism lies in his acceptance of the view "that every true universal, every continuum, is a living and conscious being." On page 28, there is a marginal note signed "WJ" (William James?): "This is too abrupt along here. Should be more mediated to the common mind."

440. Detached Ideas. Induction, Deduction, and Hypothesis (DI)
A. MS., G-1898-1, pp. 1-37 (pp. 9-12 missing), plus 15 pp. of variants.
Only the four rules given on pp. 4-7 published as 7.494n9. The remainder concerns scientific and philosophic terminology, modern science and realism (the abuse of the term "realism"), the history of the discovery of the logic of relatives, the relationship of induction and retroduction to the syllogistic figures (induction as probable inference in the third figure; retroduction as probable inference in the second figure). A marginal note by "WJ" on p. 25.

441. Types of Reasoning (Ty)
A. MS., n.p., 1898, pp. 1-31 (p. 10 missing).
The relationship between logic and metaphysics. In order to enliven his lectures, CSP mentions his early interest in philosophy, and writes of the development of his thinking about logic. The controversy beween Philo and Diodorus. Scholastic doctrine of Consequentia. Hypothetical and categorical propositions and their logical equivalence. Induction, deduction, retroduction and the syllogistic forms. Induction as probable reasoning in the third figure.

442. The First Rule of Logic (FRL)
A. MS., G-1898-1, pp. 1-38, with 3 pp. of variants.
Published as 5.574-589, with omissions. Omitted were pp. 13, 18, 22-24, 36-38 on Alexandre Dumas (CSP's attitude somewhat disparaging), pure mathematics, and the notion that truth is ambiguous, e.g., that a proposition might be true in religion but false in philosophy. The theoretical and practical sense of ''holding for true."

* 443. Causation and Force (TC)
A. MS., G-1898-1, pp. 1-35, plus discarded pp. 13-15, 13-14, 20, 28, and 2 pp. with the titles "Time and Causation" (TC) and "Time and Causality."
Published in three places in the following order: 6.66-81; 7.518-523; 6.82-72. Only the introductory first paragraph was deleted.

444. Training in Reasoning (R)
A. MS., G-1898-1, pp. 19.
MSS. 444 and 445 published, with deletions and pages missing, under the title "Training in Reasoning," The Hound and Horn 2 (July-September 1929), 398-416. Common or liberal education and the art of reasoning. The three mental operations carried on in reasoning: observation, experimentation, and habituation (the power of taking on or discarding habit).

445. Training in Reasoning (TR)
A. MS., G-1898-1, pp. 17-39, plus 5 pp. of variants.
A discussion of the several kinds of observation and experimentation. Introspection. The categories connected with the three mental operations of feeling, willing, reasoning. The commonest fallacies in retroduction, deduction, and induction.

446. [Notes]
A. MS., n.p., [c.1898], pp. 1-7.
Possibly for the lecture on "Causation and Force." See MS. 443.


447. [Lecture I]
A. MS., n.p., 1903, pp. 1-2, incomplete, (from a notebook).
The beginning of an historical introduction to the subject of reasoning. Scientific form given to logic by Aristotle.

448. [Lecture I]
A. MS,. notebook, G-1903-2a, pp. 1-48.
Published as 1.591-610, with omissions. Unpublished: Present day science suffers from a malady whose source is an argument based on the notion of a "logisches Gef,hl" as the means of determining whether reasoning is sound and whose conclusion is that there is no distinction between good and bad reasoning. This argument parallels another whose conclusion is that there is no distinction between good and bad conduct (pp. 1-12). Criticism of the defendant arguments and their premises that it is unthinkable that a conclusion be found acceptable for any other reason than a feeling of logicality and that a line of conduct be adopted for any other motive than a feeling of pleasure (pp. 33-48).

449. [Lecture I]
A. MS., notebook, G-1903-2a, pp. 37-61.
Published, in part, as 1.611-615 and 8.176 (except 176n3) (pp. 37-49 and 51-53). Unpublished: criticism of Sigwart and the notion of "logisches Gef,hl." Logic embraces methodeutic, critic, and the doctrine of signs (speculative grammar), with the ultimate purpose of the logician being the working out of a theory regarding the advancement of knowledge. Speculative grammar is neither psychology nor epistemology. Erkenntnislehre is mainly metaphysics. CSP agrees with those metaphysicians who insist that metaphysics must rest upon logic.

450. [Lecture I]
A. MS., notebook, n.p., 1903, pp. 1-26.
Improvement in reasoning requires, first of all, a study of deduction. For this, an unambiguous and simple system of expression is needed. The system in which reasoning is broken up into its smallest fragments by means of diagrams is the system of existential graphs, which CSP goes on to develop in terms of fourteen conventions.

451. [Lecture I]
A. MS., notebook, n.p., 1903, pp. 1-21.
Refutation of the view that there is no distinction between good and bad reasoning or, for that matter, good and bad conduct, because in both cases the distinction rests on feeling which, in turn, rests upon a confusion of the pleasure afforded by the inference with the approval of it.

452. [Lecture I]
A. MS., notebook, n.p., 1903, pp. 1-14.
The purpose of logic; the division of logic into speculative grammar, critic, and methodeutic. Why "methodeutic" as a name is preferred to "method" or "methodology." CSP's exposition begins with logical syntax.

453. [Lecture I]
A. MS., notebook, n.p., 1903, pp. 1-37.
Science hampered by the false notion that there is no distinction between good and bad reasoning. This notion related to the German idea that bases logic on feeling.

454. Lectures on Logic, to be delivered at the Lowell Institute. Winter 1903- 1904. Lecture I
A. MS., notebook, n.p., 1903, pp. 1-26.
Existential graphs as a system for expressing any assertion with precision is not intended to facilitate but to analyze necessary reasoning, i.e., deduction. The system introduced by means of four basic conventions (here called "principles") and four rules ("rights") of transformation.

455. [Lecture II]
A. MS., notebook, n.p., 1903, pp. 1-31.
The first and third parts of an introduction to the alpha and beta parts of the system of existential graphs; MS. 456 is the second part.

456. Lowell Lectures. Lecture 2. Vol. 2
A. MS., notebook, n.p., 1903, pp. 40-66.
The second of a three-part introduction to the alpha and beta parts of existential graphs. For the first and third parts, see MS. 455.

457. CSP's Lowell Lectures of 1903. 1st Draught of 3rd Lecture
A. MS., notebook, n.p., begun October 2, 1903, pp. 1-10.
On a kind of decision procedure (in terms of alpha-possibility) for existential graphs. Cf. MS. 462.

458. Lowell Lectures. 1903. Lecture 3. 1st draught
A. MS., notebook, n.p., 1903, pp. 1-33.
Science, mathematics, and quantity. Pure mathematics (the science of hypotheses) is divided in accordance with the complexity of its hypotheses. Simplest mathematics is the system of existential graphs. Doctrine of multitude: Cantor's work on collections. Understanding requires some reference to the future to an endless series of possibilities. Achilles and the Tortoise Paradox.

459. Lowell Lectures. 1903. Lecture 3
A. MS., notebook, n.p., 1903, pp. 1-41.
The words "Won't do" (by CSP) appear on the cover of the notebook. Definition of "mathematics." Denial that mathematics is reducible to logic. Alternative positions considered. Existential graphs; qualities; collection; multitude (Whitehead and Russell); substantive possibility.

460. [Lecture III]
A. MS., notebook, G-1903-2a, pp. 1-22.
Published, in part, as 1.15-26 (pp. 2-21). Gamma graphs, the third part of existential graphs, rendered intelligible by CSP's categories of Firstness, Secondness, Thirdness. And without the gamma graphs, multitude, infinity, and continuity are not easily explained. The peculiarity of gamma graphs is that they make abstractions (mere possibilities) and laws the subjects of discourse.

461. Lowell Lectures of 1903 by C. S. Peirce. Second draught of Lecture 3
A. MS., notebook, n.p., September 30, 1903, pp. 1-9; plus 2 cards which were found inserted among the unnumbered pages of the notebook.
Multitude; serial order of qualities; continuity.

462. CSP's Lowell Lectures of 1903 2nd Draught of 3rd Lecture
A. MS., n.p., October 5, 1903, pp. 2-88 (pagination by even numbers only), incomplete.
Alpha part of existential graphs: permissible operations. The Beta part. Difference between alpha-impossibility and beta-impossibility summarized [cf. MS. 457]. The Gamma part concerns what can logically be asserted of meanings. The distinction between regulative and constitutive (in Kant). The logical doctrine called "Pragmatism." CSP claims that he has been unjustly called a sceptic, a second Hume. The "joke" about opium's dormitive virtue. Possibility and necessity (Locke's confusion). Qualities as mere possibilities. Relations are qualities of sets of subjects. Dyadic and triadic relations. All triadic relations are, more or less, thoughts. Doctrine of signs; icons, indices, and symbols.

463. Lowell Lectures of 1903. Lecture III. 2nd Draught
A. MS., notebook, n.p., 1903, pp. 11-17 (pp. 1-9 are mathematical notes and have nothing to do with the lecture).
On multitude and collection.

464. CSP's Lowell Lectures of 1903. Part 1 of 3rd draught of 3rd Lecture
A. MS., notebook, G-1903-2a, begun October 8, 1903, pp. 1-64, 68.
Published in two places: 1.324 and 1.343-349 (pp. 30-34 and 36-64 respectively). Note that part of 1.349 comes from page 68 of MS. 465, with p. 68 of that manuscript continuing p. 64 of this one. Omitted is a discussion of existential graphs, especially alpha and beta possibilities (pp. 1-30) and a discussion of the category of Firstness (pp. 34-36).

465. CSP's Lowell Lectures of 1903. 2nd Part of 3rd Draught of Lecture III
A. MS., notebook, G-1903-2a, October 12, 1903, pp. 68-126; A1-A8.
Published, in part, as 1.521-544 (pp. 68-126, with only the first and last paragraphs deleted). Pages A1-A8, unpublished, are mainly a reply to a listener's note asking, "What makes a Reasoning to be sound?" The note itself (dated November 27, 1903) has been inserted opposite p. A1. Also unpublished is material on the beta part of existential graphs.

466. Useful for 3rd or 4th?
A. MS., notebook, n.p., 1903, pp. 1-28, unfinished, with two p. 19's, both of which leave text intact.
Mathematics and logic; existential graphs introduced initially to illuminate the nature of pure mathematics, and then used in the discussion of multitude.

467. C. S. Peirce's Lowell Lectures for 1903. Lecture 4.
A. MS., 2 notebooks, G-1903-2a, pp. 1-96.
Two volumes comprise the fourth lecture, with the first volume entitled "Gamma Part of Existential Graphs." Volumes I and II (pp. 1-96) published as 4.510-529, with deletions. Deleted: brief history of exact logic, i.e., logic begun by De Morgan, including CSP's entitative and existential graphs (pp. 8-18). Opium's dormitive virtue; abstraction, including Hegel's abuse of the term (pp. 66-78).

468. CSP's Lowell Lectures of 1903. Introduction to Lecture 5
A. MS., notebook, n.p., December 4, 1903, pp. 1-9.
Gamma part of graphs continued (but quickly abandoned). Graphs of logical principles. Beta part.

469. Lowell Lectures. 1903. Lecture 5. Vol. 1
A. MS., notebook, n.p., 1903, pp. 2-74.
Doctrine of multitudes. Breadth and depth. Reference to Bertrand Russell's Principles of Mathematics in connection with the question, Is a collection which has but a single individual member identical with that individual or not? Cantor's system of ordinal numbers.

470. Lecture 5,. Vol. 2
A. MS., notebook, n.p., 1903, pp. 76-158.
At the beginning CSP offers the following plan for his lecture series: "1. What makes a reasoning sound, 2. Existential Graphs, Alpha and Beta, 3. General Explanations, Phenomenology and Speculative Grammar, 4. Existential graphs, Gamma Part, 5. Multitude, 6. Chance, 7. Induction, 8. Abduction." Collection and multitude; syllogism of transposed quantity; Fermatian reasoning; first and second ultranumerable multitude; continuity (pp. 78-122). Gamma graphs (pp. 124-138). The beginning of a lecture occasioned by the death of Herbert Spencer. Mentioning his personal encounters with Spencer, CSP writes on Spencer's evolutionism and his influence on philosophy generally (pp. 140- 158) .

471. [Lecture V]
A. MS., notebook, n.p., 1903, 10 pp.
On multitude and collection.

472. Lowell Lectures. 1903. Sixth Lecture. Probability
A. MS., 2 notebooks, G-1903-2a, pp. 2-130.
Published, in part, as 6.88-97 (pp. 8-62). Omitted: the relationship between logic and mathematics; independence of logic from metaphysics but not vice versa (pp. 2-7). Doctrine of chances: reference of the word "chance," in all its meanings, to variety; chance not a matter of ignorance but of the immense diversity of the universe; the tendency of this diversity to grow into uniformities; the conception of the "long run"; mathematical theory of probabilities; probability as requiring some objective meaning; CSP's advice to stop talking of probabilities in connection with the doctrine of chances and to talk instead of ratios of frequency; the difficulty most people have of understanding why it is not logically impossible that an event whose probability is zero should nevertheless occur; and, finally, Hume on miracles (pp. 62-130).

* 473. C. S. Peirce's Lowell lnstitute Lectures. 1903, Seventh Lecture. Introduction Vol. I
A. MS., notebook, G-1903-2a, pp. 2-92.
Published, in part, as 7.110-130 (pp. 36-84). Omitted from publication: a discussion of deduction, induction, and abduction (pp. 2-35). The rationale of induction; Ockhamists versus Scotists; John Stuart Mill and the question of the uniformity of nature (pp. 85-92).

474. [Lecture VII]
A. MS., notebook, n.p., 1903, pp. 96-152.
Volume II of the Seventh Lecture. Law, uniformity, and variety. Critical comments on Mill's views on the uniformity of nature. For CSP it is obvious that nature is not uniform, but that variety is nature's leading characteristic. His realism is opposed to Mill's nominalism. The problem of induction, with solutions by Abbe Gratry, Laplace, and CSP.

475. C. S. Peirce's Lowell Lectures of 1903. Eighth Lecture, Abduction
A. MS., notebook, G-1903-2a, pp. 2-92 (pagination is somewhat irregular but the text is continuous).
Volume I. Published, in part, as 5.590-604 (pp. 28-92). Unpublished: the division of reasoning into deduction, induction, and abduction as deriving from Aristotle and Boole. The relationship of the three kinds of reasoning to the syllogism. A brief review of CSP's own reflections on the kinds of reasoning, noting articles he published and the errors and confusions these contain.

476.C. S. Peirce's Lowell Lectures of 1903. Eighth Lecture, Abduction. Vol. 2. Pythagoras
A. MS., notebook, G-1903-2a, pp. 94-168.
Only p. 95 published: 7.182n7. Unpublished are several examples of abduction. Life of Pythagoras as affording the prime example. CSP treats historical topics about which there has been considerable debate, claiming that his abductions have been verified - contrary to the expectations of historians - on five occasions.

477. Notes for a Syllabus of Logic
A. MS., notebook, n.p., June 1903, 17 pp., incomplete.
The syllabus was intended as a supplement to the Lowell Lectures of 1903. Ingredients of the phaneron. Phaneroscopic descriptions of consciousness. Aristotle's categories and predicables.

* 478. Syllabus of a course of Lectures at the Lowell Institute beginning 1903, Nov. 23. On Some Topics of Logic (Syllabus)
A. MS., G-1903-2b and G-1903-2d, pp. 1-168 (pp. 106-136 missing); a second title page; pp. 2-23 of a revised section; 69 pp. of variants; and a corrected copy of the printed syllabus.
A second version of the above title, "A Syllabus of Certain Topics of Logic," became the title of the pamphlet published by Alfred Mudge & Son, Boston, 1903. The pamphlet, however, is not an exact copy of the manuscript, several sections having been omitted. From the manuscript, pp. 1-26 and 137-149 were published in the pamphlet as pp. 1-14 and 15-20 respectively. Transformation rules for existential graphs are treated in an abridged form on pp. 20-23 of the pamphlet. For publication of the pamphlet in the Collected Papers, see G-1903-2b. Pages 43-46, 47-48, 48-50, and 50-89 published respectively as 2.274-277, 2.283-284, 2.292-294, and 2.309-331. Omitted from publication: sundry logical conceptions; Peircean categories of Firstness, Secondness, Thirdness; the possibility of certain kinds of separation of thought; dissociation, precision, discrimination; the categories in their forms of Firstness (phenomenology); the normative sciences and their interrelations; the division of logic into speculative grammar, logical critic, and methodeutic (pp. 27-42). Arguments as symbols; classification of arguments into deduction, induction, and abduction; etymology of deduction (pp. 89-105).


479. On Logical Graphs (Graphs)
A. MS., G-c.1903-3, pp. 1-64; plus 30 pp. of several starts.
Published as 4.350-371, with deletions. Deleted: two complicated examples on pp. 5-8, 21-22 and some random comments, concerned chiefly with Eulerian diagrams and the history of logical graphs.

480. On Logical Graphs (Acad. Graphs)
A. MS., n.p., n.d., pp. 1-l9, plus 3 pp. of variants.
Apparently an early form of what was to evolve into existential graphs. Formation and transformation rules of the system.

481. On Logical Graphs
A. MS., n.p., n.d., p. 1-10.
A system of graphs using "curves convex inwards," and presumed to be an improvement over Euler's diagrams and logical algebra.

482. On Logical Graphs
A. MS., n.p., [c. 1896-98], pp. 1-30; plus 192 pp., partially ordered, but mainly a confusion of alternatives or rejects.
Includes partial drafts of several different papers (e.g., parts of an early draft of 3.468 ff.). Application of topology to logical graphs; examples and rules for interpretation; illative transformations.

483. On Existential Graphs
A. MS., n.p., [c.1901], pp. 1-9, plus 21 pp. of variants.
Several attempts to write the same pages. Basic conventions of the system of existential graphs. A reference to the Monist article of January 1897.

484. On Existential Graphs (F4)
A. MS., n.p., 1898, pp. 1-28; 11-15, 20.
Application of topology to logical graphs, followed by a development of the constitutive conventions of existential graphs. Remarks on the equivalence between existential graphs and familiar (ordinary) language. Elementary rules of illative transformation deduced from basic rules of existential graphs.

485. On Existential Graphs (EG)
A. MS., n.p., n.d., pp. 1-2, with at least three other attempts, none going beyond p. 2, and with another six attempts to write the same, but under the subtitle "Rules of (their) Illative Transformation."

486. Existential Graphs
Amanuensis, with marginal notes in CSP's hand, n.p., n.d., p. 1-10. Twenty-three "Rules for their Illative (Logical) Transformation."

487. [Transformation Rules for Existential Graphs]
A. MS., n.p., n.d., 5 pp.
Seventeen rules are given, the last ten of which are derived from the first seven (or basic rules for existential graphs).

488. Positive Logical Graphs (PLG)
A. MS., n.p., n.d., pp. 1-6, plus 2 pp. of variants.
"Logical graphs" was the early name for what later became existential graphs. Definitions and conventions of the system.

489. Investigation of the Meaning It Thunders
A. MS., n.p., n.d., pp. 1-8.
An essay in which the meaning of the cut (or circle) in the example It thunder is derived from certain basic rules for existential graphs.

490. [Introduction to Existential Graphs and an Improvement on the Gamma Graphs]
A. MS., notebook, G-1906-2.
CSP wrote on the cover of the notebook: "For the National Academy of Sci. 1906 April Meeting in Washington." Published, with omissions, as 4.573-584. Cf. MS. 480.

491. Logical Tracts. No. 1. On Existential Graphs
A. MS., n.p., [c 1903], pp. 1-12; 1-10; 1-3; 11 pp. of variants. Logical and existential graphs (pp. 1-12). Basic definitions and principles of representation (pp. 1-10). Icon, index, symbol (pp. 1-3).

492. Logical Tracts. No. 2. On Existential Graphs, Euler's Diagrams, and Logical Algebra
A. MS., G-c.1903-2, pp. 1-141 (pp. 85 and 120 missing), with 104 pp. of variants; plus several alternative sections (pp. 3-41, with 5 pp. of variants; 18-41, with 4 pp. of variants; 19-39, with 15 pp. of variants).
Published, in part, as 4.418-509 (pp. 1-141, with omissions). Omitted: a translation of Euclid and a pair of complicated examples. From alternative sections: the relationship of symbols to past, present, and future; replicas; si signs, bi signs, and ter signs (pp. 19-39 of one section. Connexus and lines of identity; a selective connexus; phenomenology; representamens (icons, indices, symbols); si signs, bi signs, ter signs (pp. 18-41 of another section).

493. The Principles of Logical Graphics
A. MS., small red leather notebook, n.p., n.d.
Over one hundred-fifty examples of existential graphs illustrating "fundamental assumptions." Illative transformations. Rules of existential graphs: erasure and insertion, iteration and deiteration.

494. Existential Graphs: A System of Logical Expression
A. MS., standard size notebook, n.p., n.d.
A development of the existential graphs from "Constitutive Conventions" up to proofs of theorems, with good examples of graphs. Also three pages on a "Deduction of the Rule of Addition of Integers in the secundal system."

495. Logical Graphs
A. MS., small notebook, n.p., n.d.
Two attempts at a presentation of the existential graphs. Neither attempt gets beyond the "Constitutive Conventions."

496. [Notes on Graphs]
A. MS., notebook (Cyclone Composition Book), n.p., n.d.

497. [Notes on Graphs]
A. MS., small notebook, n.p., June 1897.
Note inscription on first page: "C. S. Peirce from Francis Lathrop 1897 June 15." Basic rules and commentary.

498. On Existential Graphs as an Instrument of Logical Research
A. MS., notebook (Harvard Cooperative), n.p., n.d.
Evidently prepared as an address to the American Academy. CSP mentions that existential graphs were discovered by him late in 1896, but that he was practically there some fourteen years before. The graphs were not invented to serve as a calculus, but to dissect the inferential process. Two puzzles examined with a view toward testing the system of graphs. One puzzle concerns the relation of signs to minds, and of communication from one mind to another. The other puzzle concerns the composition of concepts and the nature of judgment or, antipsychologically speaking, propositions, Signs; reality; conventions of the system of existential graphs.

499. On the System of Existential Graphs Considered as an Instrument for the Investigation of Logic
A. MS., notebook (Harvard Cooperative), n.p., n.d.
The value of logical algebras. Logic as a calculus: CSP's minority report. The way in which the system of existential graphs serves the interest of the science of logic. Solutions suggested by the method of existential graphs to two problems, one of which concerns the relation of signs to minds and the other the composition of concepts. Existential relations of signs, from which is deduced a classification of signs and a nomenclature useful in describing existential graphs.

* 500. A Diagrammatic Syntax
A. MS., n.p., December 6-9, 1911, pp. 1-19.
A letter to Risteen on existential graphs.

501. [Worksheets on Graphs]
A. MS., n.p., n.d., 92 pp.
The worksheets are concerned mainly with two axioms: Something is scriptible and something is unscriptible.

502. Peripatetic Talks. No. 2 (PT2)
A. MS., n.p., n.d., pp. 1-4, plus 2 pp. of two other starts.
On the presuppositions of logic, e.g., that there is error, that - up to a point - it is eradicable, that there is some method of eradicating it. On the essential characteristics of belief.

503. Peripatetic Talks. No. 4 (PT4)
A. MS., n.p., n.d., pp. 1-6; 3-5.
On the five fundamental rules of existential graphs, and some of their consequences.

504. Peripatetic Talks. No. 6 (PT6)
A. MS., n.p., n.d., pp. 1-7.
On existential graphs. A defect in the system: There is no proper form for expressing the proposition that "There is some clergyman who praises every lawyer each to a doctor, so that for every possible distribution of such praises, there is a distinct clergyman who performs the praise."

505. Peripatetic Talks. No. 7 (PT7)
A. MS., n.p., n.d., pp. 1-2, with another 1 p. start.
The proposal is made to restate the fundamental principles of existential graphs in a new form. Three rules are listed and illustrated.

506. Existential Graphs
A. MS., small brown notebook, n.p., n.d.
List of rules: Rule XI - Rule XXIII. On back pages of notebook, CSP forms 62 words, beginning with the letter C, from the letters of the word "instruction," the purpose of which is not evident.

507. [Existential Graphs]
A. MS., n.p., n.d., 9 pp.
Beta and gamma graphs, with algebraic translations. Rules of transformation.

508. Existential Graphs. Rules of Transformation. Pure Mathematical Definition of Existential Graphs, regardless of their Interpretation (Syllabus B)
A. MS., n.p., n.d., pp. B1-B6.
An early draft of 4.414-417, together with some discussion of the gamma part of existential graphs.

509. Gamma Graphs
A. MS., n.p., n.d., pp. 1-5.

510. [Notes on Graphs]
A. MS., n.p., n.d., 12 pp.

511. (D)
A. MS,. n.p., n.d., pp. D3-D7, with 7 pp. of variants.
Hypotheses concerned with permissions and prohibitions and with possibility and necessity. These pages are part of MS. 3.

512. (SM)
A. MS., n.p., n.d., 3 pp.
These pages are part of MS. 2.

513. (FL)
A. MS., n.p., n.d., pp. 27-98, incomplete and in some disorder, with missing sections and many alternatives and/or rejects.
The first part of the manuscript is concerned with logical algebra. CSP's graphical method (pp. 52-78), with a note that "my cumbrous General Algebra with all its faults, seems preferable." Pages 78 ff. present another algebraic system which is labelled the "Algebra of Dyadic Relatives" and which "seems to have fascinated Professor Schr^der much more than it has me." The Algebra of Triadic Logic is mentioned ("But I have never succeeded in perfecting it").

* 514. [Fragments on Existential Graphs]
A. MS., n.p., [1909], 53 pp.


515. On the First Principles of Logical Algebra (First Prin)
A. MS., n.p., n.d., pp. 1-34, with 25 pp. of variants.
Indecomposable transformations. Rules of transformation, with commutation and association developed from these rules. Implication; contradiction and excluded middle; aggregation and composition. Ethics of terminology applied to the case of Boole's creation of logical algebra. Transitive relations; incompossibility; identity and lines of identity. Propositions and signs; universal, particular, individual propositions; subject of propositions. Among the variants, the following topics occur: lines of identity; individual, definite, and singular terms; rules for existential graphs. Also the initial discussion of categoriology in connection with logical terms.

516. On the Basic Rules of Logical Transformation
A. MS., n.p., n.d., pp. 1-51, plus 45 pp. of variants.
First principles of Boolean algebra as extended by CSP to the logic of relatives with a view toward developing certain other notations. The system of symbols employed is that of existential graphs.

A. MS., n.p., n.d., pp. 1-85, with 81 pp. of variants.
Part I. A reference to CSP's "New Elements of Mathematics," for which no publisher could be found, and mention of the loss of CSP's power of writing about logic in a mathematical way, which, in point of fact, he no longer admires. Part II. On definition, postulate, axiom, corollary, theorem; signs, interpretants, entelechy; theory and practice; real relations and reactions; judgment and proposition; judgment and assertion; belief, affirmation, and judgment; doctrine of signs. Criticism of nominalism. The nature of "law"; event and fact; internal and external causes. Law signifies more than mere uniformity; it involves real connections. An improvement upon the traditional doctrine of causation. Symbols unable to exert force, but do govern things (for they are laws). A symbol signifies what it does, as in the feeling of "having been in a present situation before" - a case of accident, not of inherent necessity. Symbols as having grades of directness to the limit of being their own significations, and as having the power to reproduce themselves and to cause real facts. Reality as the limit of the endless series of symbols. Symbols and language, with language unable to provide a basis for logic. "How the constitution of the human mind may compel men to think is not the question; and the appeal to language appears to me to be no better than an unsatisfactory method of ascertaining psychological facts that are of no relevancy to logic. But if such appeal is to be made (and logicians generally do make it, in particular their doctrine of the copula appears to rest solely upon this) it would seem that they ought to survey human languages generally and not confine themselves to the small and extremely peculiar group of Aryan speech."

518. [The Regenerated Logic]
A. MS., G-1896-6a, pp. 1-29, 17-21, 25-28.
This is the manuscript of the "The Regenerated Logic" (Monist, Vol. 7, pp. 19-40, 1896) which was reprinted as 3.425-455.

519. Studies in Logical Algebra
A. MS., notebook, n.p., May 20-25, 1885.

520. [Schroeder's Logical Algebra]
A. MS., n.p., n.d., pp. 1-27, incomplete; 41-44; plus 5 pp. of variants.

521. Schroeder's Logic of Relatives
A. MS., n.p., n.d., pp. 1-33, with 19 pp. of variants.

* 522. Notes on Schroeder's Logic of Relatives
A. MS., small red notebook, n.p., n.d.; and 1 p. continuing the comparison of CSP's symbolism with Schroeder's begun on pp. 38-41 of the notebook.

523. Notes on Schroeder's 3rd Volume
A. MS., n.p., n.d., 2 pp.

524. [Schroeder and the Logic of Relations]
A. MS., n.p., n.d., pp. 1-9.

* 525. [Fragment on Schroeder]
A. MS., n.p., n.d., p. 10.

* 526. Logic of Relatives. No. 2
A. MS., n.p., n.d., pp. 1-4; plus pp. 2-4 of Paper I.
Papers I and II are part of a series announced by the Pike County Press, Milford, Pa., 1895-96, but never published.

* 527. On the Algebra of Logic
A. MS., n.p., n.d., 5 pp. of a manuscript draft; 12 pp. of a typed draft (corrected by CSP); a reprint of "On the Algebra of Logic: A Contribution to the Philosophy of Notation" (G-1885-3); and 2 pp. of fragments.
Reprint of an article for the American Journal of Mathematics, Vol. 7, No. 2, 1885. Published again as 3.359-403, except 369n (p. 230), with an undated marginal note, 384n1.

528. On the Algebra of Logic
Reprint, G-1880-8.
Reprint of an article for the American Journal of Mathematics, Vol. 3, 1880. Published again as 3.154-251, except 154n1 and 200n* (p. 128), with an editor's marginal corrections and with the revisions of 1880, c.1882, and undated.

* 529. Description of a Notation for the Logic of Relatives, resulting from an Amplification of the Conceptions of Boole's Calculus of Logic
Reprints, G-1870-1.
Two reprints from Memoirs of the American Academy of Arts and Sciences (communicated January 26, 1870). One reprint is annotated by CSP; the other contains marginal notes, not by CSP. Published again as 3.45-149, except 45n*, with revisions from CSP's own copy.

530. A Proposed Logical Notation (Notation)
A. MS., n.p., [C.1903], pp. 1-45; 44-62, 12-32, 12-26; plus 44 pp. of shorter sections as well as fragments.
Ethics of terminology. The history of logical terms and notations, and CSP's recommendation of "the best algebraical signs for logic." On the Stoic division of hypothetical propositions. CSP's division of hypothetical propositions. Graphs, algebra of dyadic relations, linear associative algebra, nonions.

* 531. Brief Account of the Principles of the Logic of Relative Terms
A. MS., n.p., n.d., 13 pp. (fragmentary).
Explanation of the three kinds of logical terms: absolute, simple relative (dyadic), and conjugative (triadic or higher). The logical copula.

532. The Logic of Relatives, Qualitative and Quantitative
A. MS., n.p., [c1885], 13 pp. and 7 pp. of two drafts; plus 7 pp. of fragments. Two drafts distinguishable, the shorter of which has the title "The Logic of Relations, Qualitative and Quantitative." Algebraic notation explained, and principal rules of transformation, with proofs, provided. Its advantage over the Boolean algebra consists in the fact that it can do everything the Boolean algebra does without employing any superfluous symbols.

533. On the Formal Classification of Relations
A. MS., n.p., [1880's], 13 pp. (fragmentary).
Different starts on the same problem of formal classification. The classification of relatives with respect to single elements, pairs of elements, continuum of elements, and infinity of elements.

534. The Logic of Relatives
A. MS., n.p., n.d., 6 pp.
The classification of relations with respect to the two broad classes of logical and real. Under logical relations, CSP distinguishes four classes: incompossibility, identity, otherness, coexistence. Under real relations, he distinguishes the following: aliorelations, concurrencies, anti-aliorelations, anti-concurrencies, variform relations.

535. [A Boolean Algebra with One Constant]
A. MS., G-c.1880-1, 7 pp.
Published in entirety: 4.12-20.

* 536. Dual Relatives
A. MS., n.p., 1889, 17 pp.
Several attempts at the same paper. Distinction between logical and real relations. The four principal logical relations and the five classes of real relations. Boolean algebra. Cf. MS. 533.

537. An Elementary Account of the Logic of Relatives
TS., n.p., n.d., 10 pp. of which some are duplicates.

538. Divisions and Nomenclature of Dyadic Relations (Dy. Rel.)
A. MS., n.p., [C.1903], pp. 1, 3-6, 9-12, 15, 19, 21-23, 29-30, and variants. Earlier draft of MS. 539. See G-1903-2c.

539. Nomenclature and Divisions of Dyadic Relations (Syllabus)
A. MS., n.p., [c.1903], pp. 106-135 (p. 134 missing).
Modal and existential dyadic relations. See G-1903-2c.

540. Nomenclature and Division of Triadic Relations, as far as they are determined (Syllabus)
A. MS., n.p., n.d., pp. 134-155, plus 7 pp. of variants.
Provisional division of triadic relations into relations of comparison, performance, and thought. The three correlates of any triadic relation. Doctrine of signs: classes of signs.

541. (Syllabus 7)
A. MS., n.p., n.d., 1 p.

542. (Class of Dyadic Rel.)
A. MS., n.p., n.d., pp. 2-4.

543. [Triadic Relations]
A. MS., n.p., n.d., pp. 29-37 (3 folded sheets).
Reduction of tetradic relations. CSP maintains that every relation higher than triads is resolvable into a combination of triadic relations, and he conjectures that Royce holds the position that every dyadic relation is really a triadic one.

544. The Logic of Relations
A. M.S., n.p., n.d., pp. 1-9, plus 6 pp. of variants.
The three grades of clearness. Relations in their different grades of clearness.

545. [Notes on the Logic of Relatives]
A. MS., n.p., n.d., 10 pp.

546. Comments on Cayley's "Memoir on Abstract Geometry" from the point of view of the Logic of Relatives
A. MS., n.p., n.d., 5 pp.

547. Logic of Relatives
A. MS., n.p., n.d., 18 pp.
An attempt to state the main results of the work of Augustus De Morgan and A. B. Kempe. The remainder of the paper is fragmentary but involves, in part, a statement and proof of the principles of nonrelative logic; for example, those of identity, modus ponens, and commutation.

548. Logic of Relatives
A. MS., notebook, n.p., n.d.
Association formulae. The external product of pairs. The converse. Relations of combination of four terms. Axioms of number. Relative of simple correspondence.

549. [Algebra of Logic]
A. MS., n.p., [C.1882-83], pp. 1-10.
Reference to a note by Mrs. Ladd-Franklin on the Constitution of the Universe (JHU Studies in Logic, p. 61). Principle of excluded middle. Cf. MS. 560.

550. [Algebra of Logic]
A. MS., n.p., n.d., 2 pp.
Ascertaining by algebra whether the answer to any question, as "Whether Elijah was caught up in heaven," is contained in what we already know.

551. A Problem in Testimony
TS., n.p., n.d., 4 pp.
The solution to a problem found in Boole's Laws of Thought. CSP's solution is, in effect, the same as Boole's though expressed differently.

552. [Relative and Non-relative Terms]
A. MS., n.p., n.d., 5 pp.

553. [On the Algebra of Relatives]
A. MS., n.p., n. d., 33 pp.
Various pages for a proposed book on logic, mostly on the algebra of relatives. Other topics covered are logical graphs, induction, deduction, and the statistical syllogism (probability).

554. [Logic of Relatives]
A. MS., n.p., n.d., 4 pp.

555. [Logic of Relatives]
A. MS., n.p., [1892?], 18 pp.

556. [Logic of Relatives]
A. MS., n.p., n.d., sections of 12 pp., 8 pp., and 3 pp.

557. [Logic of Relatives]
A. MS., n.p., n.d., 21 pp.

* 558. [Logic of Relatives]
A. MS., n.p., n.d., pp. 14-28.

559. [Logical Algebra]
A. MS., n.p., n.d., 121 pp.
Notational conventions. The introduction of superfluous elements into algebra for purposes of balance and homogeneity. Rules of algebraical procedure. The three laws of thought: identity, contradiction, and excluded middle. Logic and the uses of ordinary language. Aristotle's propositional forms.

560. [Logical Algebra]
A. MS., n.p., n.d., pp. 1-27, incomplete.
Principle of excluded middle. Reference to G-1880-8 and an attempt to show that a logical algebra can be constructed without the special signs and as quantifiers. Cf. MS. 549

561. The Boolian Calculus
A. MS., n.p., n.d., 2 pp.
Boolean algebra and the problem of continuity.

562. Note on the Boolian Algebra
A. MS., n.p., n.d., pp. 1-4.

563. [An Improvement on Boole's Treatment of the Function]
A. MS., n.p., n.d., pp. 1-4.

564. Boolian Algebra. First Lecture
A. MS., n.p., n.d., 8 pp. (fragmentary).
Introductory remarks to a lecture on Boole with discussions of improvements (by other logicians) of the Boolean algebra.

565. Chapter II. Interpretation of Logistic
A. MS., n.p., n.d., 10 pp.

566. Chapter III. Development of the Boolian Notation
A. MS., n.p., n.d., 1 p.

567. [A Note to "On the Algebra of Logic: A Contribution to the Philosophy of Notation" (G-1885-3)]
A. MS., C-1885-3 (c.1885), 47 pp., and a crumbling copy (not in CSP's hand) on the same subject. See sup(2)G-1885-3.
Published in entirety as 3.403A-403M.

568. Chapter III. Development of the Notation, begun
A. MS., n.p., n.d., 2 pp.

569. [Algebraical. Rules. to which Sign -< is Subject]
A. MS., n.p., n.d., pp. 1-6; 1-4, with a variant p. 4.

* 570. Sketch of the Theory of Non-Associative Multiplication
A. MS., n.p., n.d., pp. 1-5, incomplete.

571. Logical Addition and Multiplication
A. MS., n.p., n.d., pp. 1-6.

572. [Non-Commutative Multiplication and other Topics]
A. MS., n.p., n.d., 15 pp.

573. [Logical Algebra]
A. MS., n.p., n.d., 28 pp.
Algebra of the copula. Special modification of the Boolean algebra. The faults of ordinary language as an instrument of logic. Ordinary language is more pictorial than diagrammatic, serving well the purposes of literature but not of logic.

* 574. [Notes on Logical Algebra]
A. MS., n.p., n.d., 45 pp.
Negative and converse. Fundamental formulae of converse. Copulas.

575. [Notes on Logical Algebra]
A. MS., n.p., n.d., 50 pp.
These pages are devoted mainly to the copula of inclusion. Brief comments on the uses of logical algebra and on the alleged connection between logical algebra and the doctrine of the quantification of the predicate.

576. Of the Copulas of Algebra
A. MS., n.p., April 27, 1871, 8 pp.

577. Algebra of the Copula
A. MS., n.p., n.d., 7 pp., representing four starts.

578. Algebra of the Copula
A. MS., n.p., n.d., 1 p.

579. Algebra of the Copula
A. MS., n.p., n.d., 76 pp.

580. The Mathematics of Logic
A. MS., n.p., n.d., 1 p.
Various ways of expressing inclusion. CSP introduces a new sign of inclusion: A B.

581. Notes on Logic
A. MS., notebook, n.p., 1902.
On the demonstrative part of arithmetic; the formal Boolean; haecceity.

582. Boolian Algebra
A. MS., n.p., n.d., 1 p.

583. Notes on History of Algebraical and Logical Signs
A. MS., n.p., n.d., 6 pp.


584. Lectures on British Logicians. Lecture I. Early Nominalism and Realism
A. MS., G-1869-2, pp. 1-14; 1-17 ("Lectures on British Logicians"); 2 pp. ("List of British Logicians").
The first of a series of fifteen lectures on "British Logicians," given by CSP at Harvard during 1869-70 at the request of the President of Harvard. Published, in part, as 1.28-29 and 1.30-34 (pp. 2-4 and 6-11 respectively). Unpublished are CSP's reflections on the history of logical controversies of the medieval period and other reflections, mainly on Scotus Erigena (pp. 1, 5, 12-14). Various definitions of "logic"; distinction between psychological and logical questions; Alcuin; Aristotle's "Organon" (pp. 1-17).

585. Ockam
A. MS., notebook, n.p. [1869]; plus another notebook ("Abstract of Occam's Summa Logices").
The history of logic. Nominalism and realism, with comments on Francis Bacon and J. S. Mill.

* 586. Whewell
A. MS., notebook, n.p., [1869].

587. Notes for Lectures on Logic. To be given 1st Term. 1870-71
A. MS., notebook, n.p., 6 pp.
Problem of meaning and truth. Meaning distinguished both from the sign itself and from the thing signified. The agreement of meaning and reality. How can two things as incommensurable as meaning and reality be said to agree?

588. Preface
A. MS., G-1883-7a, 6 pp.; plus 6 pp. of an earlier draft.
The preface is to the Johns Hopkins University Studies in Logic.

589. The Critic of Arguments. III. Synthetical propositions a priori
A. MS., G-1892-1b, 52 pp.
This is presumably the third paper of The Open Court series of 1892 of which only the first two papers were published in The Open Court. Published, in part, as 4.187n1 (pp. 5-8). Omitted from any publication: geometrical propositions and the notion of synthetic propositions a priori. CSP rejects the view that, while arithmetical propositions are analytic, geometrical ones are synthetic. Properties of number: Numbers are infinite, and the Fermatian inference is applicable to the whole collection of them. Counting.

590. The Critic of Arguments. III
A. MS., n.p., 1892, 23 pp., plus 16 pp. of another draft and 6 pp. of variants.
Mathematical propositions a priori.

591. [Critic of Arguments. IV]
A. MS., n.p., 1892, 11 pp.

592. A Search for a Method. Essay I
Printed Article (annotated), G-1893-6 and G-1867-1b.
This is the printed article of 1867, "On the Natural Classification of Arguments," together with photostats of the missing pages and with additions and corrections of 1893. 2.461-561 is the 1867 article with the additions and corrections of 1893; that is, Essay I of "A Search for a Method."

593. [A Search for a Method. Essay VI]
Printed Article, G-1893-6 and G-1868-2c, pp. 249-264.
This is the printed article of 1868, "Grounds of Validity of the Laws of Logic," along with the corrections found in the margins of the pages of the article. 5.318-357 is the 1868 article with the corrections of 1893; that is, Essay VI of "A Search for a Method."

594. [A Search for a Method: Fragments]
A. MS., n.p., 1893, 131 pp.
One page has the title: "The Quest of a Method. Essay I. The Natural Classifications of Arguments." Among the topics found in these pages are questions of terminology, the algebra of the copula, forms of propositions, and the analysis of reasoning.

* 595. Short Logic
A. MS., G-c.1893-3, pp. 1-32, 33-38; plus 14 pp. of variants.
Selections published as follows: 2.286-291 (pp. 6-13); 2.295-296 (pp. 14-16); 2.435-443 (pp. 23-29, with the omission of p. 25); 7.555-558 (pp. 29-32). Unpublished are remarks on elementary philology and the definition of "logic," along with some historical footnotes.

596. Reason's Rules (RR)
A. MS., G-c.1902-3, pp. 1-47, with 11 pp. of variants.
Published, in part, as 5.538-545 (pp. 21-45). Omitted is a dialogue between author and reader, with an aside about the Hegelian dialectic. The various extra-firm beliefs which the reader has about reasoning and belief itself: the reader's logica utens. Doubt, its derivation and the psychological uneasiness associated with it. Doubt is always more or less conscious, but this is not true of belief. That a man may be quite unaware of his belief is illustrated by the Northern reaction to the South's attack upon Fort Sumter. Cf. MS. 598.

597. Reason's Rules (RR)
A. MS., n.p., [c.1902], pp 1-6.
On what reasoning is.

598. Reason's Rules (RR)
A. MS., n.p., [c.1902], pp. 1-10, with 8 pp. of variants.
The initial or present beliefs of the reader. CSP pleads for the adoption of the principle that what is beyond control is beyond criticism or, more simply stated, do not doubt what cannot be doubted. Examples of beliefs which cannot be doubted: beliefs in what is before the eyes, the existence of persons other than oneself, memory. Cf. MS. 596.

599. Reason's Rules (RR)
A. MS., n.p., [c.1902], pp. 4-45, 31-42, and 8 pp. of fragments.
The nature of a sign. Propositions as the significations of signs which represent that some icon is applicable to that which is indicated by an index. The non-existence of propositions: propositions as merely possible. How truth and falsehood relate to propositions. Meaning as the character of a sign. Meaning and value are related: meaning as the value of a word (or the value of something for us is what that something means to us). The reference of meaning to the future.

600. (RR)
A. MS., n.p., [c.1902], 3 loose sheets, numbered 5, 35, and 36.
Critic of criticism.

601. (L)
A. MS., G-undated-13, later than the Minute Logic, but before 1908, pp. 1-33, with g pp. of variants; pp. 10-31, with 7 pp. of variants.
Published, in part, as 7.49-52 (pp. 1-9). Unpublished: the meaning of "dynamical"; the distinction between relation and relationship; speculations on the survival of the human race and on the possibility of life - similar to human life - on other planets (pp. 10-33). The classification of the sciences, based upon the distinction between theoretical and practical science (pp. 10-31).

602. On Classification of the Sciences (M)
A. MS., n.p., later than the Minute Logic, but before 1908, pp. 1-16.
The general classificatory scheme of the sciences. The threefold nature of inquiry. The normative sciences of esthetics, ethics, and logic. The nature of pratical science.

603. (N)
A. MS., G-undated-13 [1905-06?], pp. 1-47, with 10 pp. of variants.
Published, in part, as 7.77-78 (pp. 20-29). Unpublished: the place of logic among the sciences; the fact that logic is a theoretical, not practical, science, even in respect to its methodeutic division (pp. 1-19). The relationship between logic and psychology, with CSP's opposition to the "psychological logicians" stated at some length (pp. 30-47).

604. Ch. I. Ways of Life (L)
A. MS., n.p., n.d., pp. 1-5.
Three types of men: men of sentiment (e.g., artists), practical men, and the unselfish seekers after truth.

605. Chapter II. On the Classification of the Sciences (Lii)
A. MS., n.p., n.d., pp. 1-17; plus pp. 1-2 ("Chapter II. The First Division of Science") .
Distinction between theoretical and practical science. The heuretic sciences.

606. Chapter III. The Nature of Logical Inquiry (Liij)
A. MS., n.p., [1905-06?], pp. 1-29, with 2 pp. of variants.
"Maiotic" method of Socrates. The Athenian Schools and the emergence of Aristotle. Why the logical treatises of Aristotle have been called the "Organon." Discussion of the point of view that logic is a practical science, with notes on the history of this point of view. Aristotle's distinction between practical science and art. Methodeutic is not a practical science.

607. Chapter III. The Nature of Logical Inquiry (Liij)
A. MS., n.p., [1905-06?], pp. 1-9.
Aristotle's distinction between practical science and art. However, in spite of Aristotle's well-earned reputation as a philosopher, he has no conception of logic as a unitary study. Utilitarian tendencies in English logicians from Thomas Wilson to John Venn.

608. Chapter III. The Nature of Logical Inquiry (Liii)
A. MS., n.p., [1905-06?], pp. 1-3.
Dedekind and Benjamin Peirce on the relationship between logic and mathematics. Is logic mathematics?

609. Chapter I. What Logic is (Logic)
A. MS., n.p., September 23-28, 1908, pp. 1-23, plus 2 rejected pp.
The need for technical terminology. Local sign (after Lotze's "Lokal-zeichen"). Comparison of Kant and Leibniz as logicians. The first impressions of sense are caused by real external objects. CSP thinks of himself as a Berkeleyian.

610. Logic. Introduction (Logic. Introd.)
A. MS., n.p., October 24 - November 28, 1908, pp. 1-10, plus 4 pp. dated October 22 and 24.
Introductory remarks to a textbook on logic, which will be concerned with both theory and practice. A discussion of literary and philosophical styles.

611. Chapter I. Common Ground (Logic)
A. MS., n.p., October 28-31, 1908, pp. 6-25.
That which is named by a noun is everything that could possibly be said of it. Definition of "nothing" as "that which is indistinct in being." Indefinite descriptions. Logical departures from grammatical usage. The term "phaneron" introduced. The nineteenth-century German logicians.

612. Chapter I. Common Ground (Logic)
A. MS., n.p., November 2-15, 1908, pp. 6-32, 32, 32-38; plus 19 pp. of variants. Phaneron. Definition of "determination." Property of word "after." Meaning as the general name of any sort of sign. Proper names.

613. Logic. Book I. Analysis of Thought. Chapter I. Common Ground. (Logic I.i)
A. MS., n.p., November 16-18, 1908, pp. 1-4.
The basis of common understanding required before an author's mind can act upon his reader's. Moral conduct: conduct that is approved upon reflection.

614. Logic. Book I. Analysis of Thought. Ch. I. Common Ground. (Logic I.i)
A. MS., n.p., November 17-20, 1908, pp. 1-12, 3, 5-6, and variants.
The common ground between author and reader: the English language and the familiar knowledge of the ordinary truths of human life. The exercise of control over our conduct: the most important business of life. The modus operandi of control. Psychology and observation. Not every observation about the human mind is a psychological observation. Remarks on modern science.

615. Logic. Book I. Analysis of Thought. Chapter I. Common Ground. (Logic I.i)
A. MS., n.p., November 28-December 1, 1908, pp. 1-29, with 8 pp. of variants.
Definition of "logic," and the pitfalls encountered on the way to a definition. Derivation of the term "science." For CSP, science refers to the collective and cooperative undertakings of men who have devoted themselves to inquiries of a general kind. Logic depends neither upon any special science nor upon metaphysics. Logic presupposes a number of truths derivable from ordinary experience or observation. These truths, handed down from the prescientific age as common sense, are not the truths of any special science or of science in general. Remarks on classification of the sciences.

616. An Appraisal of the Faculty of Reasoning (Reason)
A. MS., n.p., late, pp. 1-11, with a rejected p. 9.
An attempt to answer the query: Assuming the existence on another planet of a race of "high psychical development," would that race be able to reason as man does? Digressions on a defense of instinct and on testing, by means of mathematical examples, the reasoning power of superior minds apparently deficient in mathematical aptitude.

617. (Reason)
A. MS., n.p., late, pp. 4-18
Mathematics and reasoning. Enigma: the inability of superior minds to grasp mathematical reasoning. Analysis of logical operations involved in a simple piece of mathematical reasoning. CSP notes which of these logical operations the gifted but unmathematical mind cannot perform. Exact reasoning and common sense. Should accuracy of thought give way to sound instinct and wholesome feeling?

618. Introduction (Meaning Introd.)
A. MS., n.p., March 28-29, 1909, pp. 1-3, incomplete.
This is one of several attempts by CSP in 1909 to write an introduction to a collection of his papers on pragmatism. This introduction defines "science" in terms of what it is that animates the true scientist; namely, the dedicated search for truth for its own sake. CSP rejects both the Aristotelian notion that science is syllogistically demonstrated knowledge and the notion that science is systematized knowledge. Reference to Lady Welby's "significs."

619. Studies in Meaning (Meaning)
A. MS., G-1909-1, March 25-28, pp. 1-14, with 2 rejected pp.
Only the first paragraph published, with minor editorial changes, as 5.358n*. Autobiographical material: persons with whom the Peirce family were acquainted; CSP and his father; CSP's emotional instability; CSP's early interest in chemistry and his discovery of Whately's Logic at the age of 13; the study of Schiller's Aesthetische Briefe, followed by a study of Kant's Critique of Pure Reason and Prolegomena, out of which came CSP's lifelong devotion to the study of logic. Members of the Metaphysical Club.

* 620. Essays Toward the Interpretation of our Thoughts. My Pragmatism (Meaning Pragmatism)
A. MS., G-1909-1, April 6-May 24, 1909, pp. 1-51 (pp. 40-41 missing), with 45 pp. of variants.
Only the first sentence of the "Preface" published (7.313n1). CSP's intellectual autobiography: the Metaphysical Club and the influence of Chauncey Wright and Nicholas St. John Green on his thinking. Abbot, who attended but one meeting of the Metaphysical Club, heard CSP on that occasion arguing in favor of Scholastic realism. Half a generation later, Abbot, in a book entitled "Scientific Theism" urged the same opinion. CSP recalls the occasion of writing the 1877-78 articles for the Popular Science Monthly. Pragmatism and pragmatisism distinguished. The fallibility of human reasoning. Sound reasoning and moral virtue. The plight of university instruction in logic. Whewell and J. S. Mill. Biographical notes on Duns Scotus and Ockham. Realism versus nominalism. Nominalism, concludes CSP, leads to absolute sceptisism. The meaning of "real"; the meaning of "universal."

621. (Meaning Pragmatism)
A. MS., n.p., May 24-September 1, 1909, pp. 21-36.6, with 2 rejected pp.; plus pp. 37-42.
This manuscript continues p. 20 of MS. 620. The nominalism-realism controversy. Auguste Comte and J. S. Mill.

622. (Meaning Pragmatism)
A. MS., n.p., May 26-June 3, 1909, pp. 34-70 (p. 50 missing), 42-43, 51, and fragments.
History of logic: Mill's nominalism; individualism as only one particular variety of nominalism; Bolzano's treatise on logic; Boole's logic; Augustus De Morgan; and the logicians, A. B. Kempe and Josiah Royce.

623. (Meaning Pragmatism)
A. MS., G-1909-1, June 5-7, 1909, pp. 43-50.
Published, in part, as 1.27 (pp. 48-50). Unpublished: an historical explanation of the popularity of nominalism in CSP's day. The union of humanists and Ockhamists in opposition to the position of Duns Scotus.

624. (Meaning Pragmatism)
A. MS., n.p., June 7, 1909, pp. 51-56, with a rejected p. 53.
Essence of the method of science lies in hypotheses whose predictions turn into verifications. Mill and the false doctrine of nominalism. Law of the Uniformity of Nature and Mill's attempt to justify it by induction. Doctrine of chances.

625. (Meaning Pragmatism)
A. MS., n.p., June 12-24, 1909, pp. 51-58, 58-82, incomplete.
Mill and nominalism. What makes nominalism attractive? Mill's contradictory position: he holds with Pearson and Poincare, on the one side, and yet he stands with Whately on induction, on the other side. The Uniformity of Nature Principle. CSP regards inference as possible only because of real connections in re. Characteristics of mathematical reasoning.

626. (Meaning Pragmatism)
A. MS., n.p., June 12, 1909, pp. 52-56.
Alternate draft of pp. 52-56 of MS. 625.

627. (Meaning Pragmatism)
A. MS., n.p., June 14, 1909, pp. 59-65.
Probable continuation of pp. 51-58 of MS. 625.

628. Studies in the Meanings of our Thought. What is the Aim of Thinking? considered in Two Chapters. Chapter I. The Fixation of Belief (Meaning)
A. MS., n.p., March 1909, pp. 1-2, 2-5.
The aim of reasoning: "to find out, from the consideration of matters and things already known, something else that we had not before known." Good reasoning gives true conclusions from true premises.

629. Studies in the Meanings of Our Thoughts. What is the Aim of Thinking, considered in Two Chapters. Chapter I. The Fixation of Belief (Meaning)
A. MS., n.p., March 1909, pp. 1-2.
The importance of studying logic. Brief comment on the history of instruction in logic.

630. Studies of Meaning (Meaning)
A. MS., n.p., March 22-25, 1909, pp. 1, 3-6; plus an alternative p. 2 and an unnumbered page.
Reference to the Popular Science Monthly articles of 1877-78 and the formulation of a principle called "pragmatism." Disagreement with James who pressed the matter of pragmatism "further than Mr. Peirce, who continues to acknowledge, not the existence, but yet the reality of the Absolute, as set forth, for example, by Royce." The Metaphysical Club and some of its leading members. CSP's intellectual development. The purpose (and the success) of CSP's attempt to master several of the special sciences.

631. Preface (Meaning Preface to the Volume)
A .MS., n.p., August 24, 1909, pp. 1-4 (for p. 5, see MS. 632).
CSP writes of his many undertakings in science, ranging from chemistry to the history of science. He speaks of his own natural powers of mind as "rather below than above mediocrity," but mentions that his three strongest points have been "self-criticism, persistence, and logical analysis."

632. Preface (Meaning Preface to the Book)
A. MS., n.p., August 24-29, 1909, pp. 1-27, plus fragments.
CSP's estimation of his own mental powers. He speaks of having heard "the most extravagant estimates placed upon my mental powers." ". . . my principal deficiency, which is that my brain is small. This renders me incapable of thoroughly grasping together any considerable number of details; and one consequence is that I do not readily pass from one subject, or occupation of thought, to another; whence my persistency." Linguistic expression is not natural to CSP, who claims never to think in words, but always in some kind of diagram. His difficulties with foreign languages. "In college, I received the most humiliating marks for my themes.... My amicable teacher Professor Francis James Child . . . thought I took no pains. But I did." CSP attributes his awkwardness of linguistic expression to his left-handedness, noting that he once wrote with facility right-handed. To grasp what abstract thought is about requires more than reading about doing something - it requires actually doing it. The "literary" habit - CSP's term for it - is ruinous.

633. Preface (Meaning Preface to the volume)
A. MS., n.p., September 4-6, 1909, pp. 1.1-1.8.
Logical and psychological analysis sharply separated, without minimizing the importance of either. Logic does not rest upon psychology, although it is true to say that in the synthetical (methodeutic) part of logic, certain psychological principles ought to be considered. Logic does appeal, however, to mathematics, phenomenology, and esthetics.

634. Preface (Meaning Preface to the Book)
A. MS., n.p., September 8-17, 1909, pp. 1-27, with 3 pp. rejected; plus p. 1 of an earlier draft, dated September 7, 1909.
Criticism of the current psychological approach to logic. Ultimate assurance of the truth of the conclusion of any reasoning is faith in the governance of the universe by an Active Reason. The distinction between object of thought and the object thought about. The real object, unlike the object of thought, is not subject to the modifications of thought. Logic as general semiotic; logic considers signs in general. Relationship among object, sign, interpretant. Signs as substitutes for objects and capable of interpretation through the mind. Nothing is able to represent itself exclusively.

635. (Meaning Preface)
A. MS., n.p., September 19 - October 2, 1909, pp. 2-7.7, 8-8 2/3 (p. 8 following p. 7.1), 6-8 (p. 6 following p. 5 of the first sequence).
Logic and psychology. Logic is not concerned with what passes in consciousness, and no person's confidence in an argument is any sure sign of the argument's validity. Doctrine of chances serves to illustrate these points.

636. (Meaning Preface)
A. MS., n.p., September 22-30, 1909, pp. 6-31, plus 2 pp. of variants.
Whether there is any reason for absolute faith. Kant's criticism of Aristotle (<ber die falsche Spitzfindigkeit de vier syllogistischen Figuren") is deemed ludicrous. Kant makes validity of inference dependent on the manner in which facts are thought rather than on the facts themselves. The relationship between logic and psychology. The distinction between "assertion" and "urtheil."

637. (Meaning Preface)
A. MS., n.p., October 3-13, 1909, pp. 9-36, 27-30, 28-29, 31-36.
Tendency to guess right (but not necessarily on the first guess). Pure logic supports the general assertion that a cautious presumption may be credited if no contrary evidence is available. The discussion of such presumptions is relegated to methodeutic. Criticism of Kant's criticism of Aristotle (Kant's "<ber die falsche Spitzfindigkeit der vier syllogistische Figuren"). Criticism of Sigwart's views that existence is the only form of reality, that any inference from thought to real objects is invalid, and that we know immediately our own thought. Unity of thought as consisting in the continuity of the life of a growing idea. An introduction to CSP's theory of signs which doesn't get beyond the elementary distinctions of the theory. Iconic, indexical, and symbolic signs.

638. (Meaning Preface)
A. MS., n.p., October 4-6, 1909, pp. 14-21.
Justification of retroduction. Pure logic encourages inquiry based on hypotheses which we accept on impulse. Practical and scientific retroduction.

639. Essays on Meaning. Preface (Meaning Preface)
A. MS., n.p., October 20, [1909], pp. 1-4.
Condemnation of present day logicians. The importance of restoring logic as the foundation of a liberal education (as was the case in medieval times).

640. Essays on Meaning. Preface (Meaning Preface)
A. MS., n.p., October 22-23, 1909, pp. 1-12 (with several other pages fitting into the sequence).
The division of logic into three studies: universal grammar, critic, and methodeutic. Mill's distinction between connotation and denotation discussed. CSP's opposition to the leading schools of logic of his day that tie rationality to human consciousness by regarding human consciousness as the author of rationality. For CSP, there is no distinction more momentous than that between "is" and "would be."

641. Significs and Logic (Significs and Logic)
A. MS., n.p., November 3-18, 1909, pp. 1-24 25/26, plus 4 pp. (November 2-23).
Purpose: analysis of the relations between semeiotic (physiology of signs) and logic (theory of reasoning). Meaning of "argument." Doctrine of chances. Nominalism and realism. The meaning of the word "real." CSP refers to his review of Frazer's edition of Berkeley, in which he took the qualified realist position of Duns Scotus. Here CSP comes out for an unqualified version of realism. CSP regards himself as a disciple of Berkeley, although he is opposed to Berkeley's denial of matter as well as to his nominalism. The distinction between God's reality and God's existence. God's reality, apart from the question of God's existence, canont be doubted by anyone who meditates upon the question. Belief in God is a natural instinct. The nature of God: God is both intelligible and incomprehensible. All atheists are nominalists. Is nominalism consistent? Substance and accident. Indefiniteness: The indefinite is not subject to the principle of contradiction. Modal logic. Analogy between modes of being and modes of meaning. Biographical material: CSP writes of the conferences in Paris of leading geodesists, and he recalls an incident involving Sylvester.

642. Significs and Logic (Significs and Logic)
A. MS., n.p., November 25-28, 1909, pp. 8-25.
This manuscript continues the preceding one. The meaning of "real." The distinction between the externality and internality of fact supported by common sense. Signification of reality compared with externality of fact. Three kinds of modality. The three modes of assertion of law, of actual fast, of freedom. Principle of excluded middle does not apply to assertions of law; principle of contradiction does not apply to assertions of freedom. Both principles apply to assertions of actual fast. Sophistries of nominalism. Some of Locke's views present difficulties for CSP.

643. Studies of Logical Analysis, or Definition (Definition 1st notes)
A. MS., n.p., December 12-13, 1909, pp. 1-7, incomplete.
Purpose: discovery of the methods of dissecting the meaning of a sign. Meanings and chemical substances. The notion of valence, or attachment (the "pegs" of CSP's existential graphs). The difference between various attachments of a concept and the valences of carbon: The attachments are unlike each other; the valences are not qualitatively different. Is it the case that we always think in signs? Signs and ideas.

644. On Definition or The Analysis of Meaning (Definition: 2nd Draught)
A. MS., n.p., December 21, 1909, 1 p.
What it means to say that anything is dependent. What it means to say that any predicate is essentially true. Importance of the notion of "would be" for philosophy.

645. How to Define (Definition: 3rd Draught)
A. MS., n.p., December 22 - January 12, 1910, pp. 1-26, with a variant p. 20.
Three studies distinguished (phaneroscopy, logic, and psychology) and their order of dependence established. Feeling, volition, and thought. In regard to feeling, Hume is in error, for he is committed to the view that vividness is an element of a sensequality. The three modes of separating the elements of a thought-object are precision, dissociation, and discrimination. Volition and purpose. Resemblances as residing in the interpretation of secondary feelings. CSP's essential conservatism. He warns, however, that self-criticism, carried too far, leads to exaggerated distrust.

646. (Definition: 4th Draught)
A. MS., n.p., January 13 - February 13, 1910, pp. 7-58, with 16 pp. of variants.
Syntax of thought. Traditional as opposed to the modern logic of relatives. An inconsistenty noted in Aristotle's conception of a universal proposition. CSP s algebra of logic: Positive and negative terms are distinguished, with "positiveness" defined.

647. Definition (Definition: 5th Draught, or new, or new draught, or new work)
A. MS., n.p., February 16-26, 1910, pp. 1-26, with 22 pp. of variants.
Three grades of clearness of apprehension. Application of the pragmatic maxim to the notion of probability. Laplace's conception of probability. CSP's distinction between fact and occurrence: A fact is as much of the real universe as can be represented in a proposition; an occurrence is a slice of the universe. The failure of both Laplace and Mill to adhere to this distinction. Distinction between sciential probability and ignorantial probability. Laplacean theory of probability confuses the two.

648. Definition
A. MS., n.p., February 27-March 22, 1910, pp. 8-58, 58-60, plus 10 pp. of variants.
Page 8 of this manuscript continues p. 7 of MS. 647, and is a later draft of that manuscript. Laplace's definition of "probability." Distinction between fact and occurrence, with Laplace attributing probability to occurrences rather than facts. Probability and states of mind. Background and history of the nominalist-realist controversy. Key figures in the controversy. Scotists and Ockhamists. Humanism and nominalism. Prantl's ignorance of Scholastic logic, especially in his Geschichte der Logik. The first question to ask of a logician is whether he is a nominalist or a realist. Eleatic doctrines and nominalism. Epicurean theory of induction. The plight of original minds in America.

649. On Definition and Classification (Definition: 6th Draught)
A. MS., G-1910-1, May 27-April 12, 1910, pp. 1-40, with 3 pp. of variants.
Published, in part, as 1.312 (pp. 12-14). Unpublished: discussion of the three grades of clearness; an analysis of the idea of a straight line; on acquiring useful habits; the bearing of ultimate desires on the art of conduct. CSP notes that man's real self, or true nature, is revealed in how a man would act, not in haste, but after due deliberation. Pleasure and pain are signs of satisfaction and dissatisfaction; they are not the satisfactions and dissatisfactions themselves. Anesthetics and the question whether pain is at all necessary. The theological problem of evil. Faculty psychology and the distinctions among knowing, willing, and feeling.

650. Diversions of Definitions (Essays Definitions)
A. MS., n.p., July 20-August 5, 1910, pp. 1-46, 9-13, 40, 44-45.
Ordinal and cardinal numbers. Cardinal numbers, not partes orationis, but orationes integrae. System of existential graphs. Profundity of medieval Scholasticism. The three parts of the soul, with faculty psychology regarded as substantially true. Feeling (Firstness). Brute-will (Secondness). Reasoning (Thirdness).

651. Essays toward the Full Comprehension of Reasonings (Essays)
A. MS., n.p., July 1910, pp. 1-11, incomplete.
An attempt to devise a plan for the improvement of reasoning, beginning with the distinction between weak arguments and unsound ones. All sound arguments are either necessary or probable. Necessary reasoning is deductive; probable reasoning can be either inductive or retroductive.

652. Essays toward the Full Comprehension of Reasonings (Essays Preface)
A. MS., n.p., July 12-17, 1910, pp. 1-27, 16-19.
Purpose: improving the reader's power of reasoning. Criticism of German logic. Distinction between weak and unsound arguments. Necessary and probable reasoning. Probable reasoning as either inductive or retroductive. The three orders of induction are quantitative, qualitative and crude (simple enumeration). Qualitative induction mistaken for retroduction. Brief comments on the history of astronomy. CSP regards Kepler's investigation of the motions of the planets as the greatest feat of inductive reasoning ever accomplished. Fallibilism and the propositions of mathematics, logic, and ethics; fallibilism and common sense.

653. Exercises in Definition, or Analysis of Concepts (Essays and Concept Analysis)
A. MS., n.p., July 20, 1910, 1 p.

654. Essays (Essays 1st Pref.)
A. MS., n.p., August 17-19, 1910, pp. 1-7, 2-3.
Note: This manuscript was meant to serve as a "Preface," with MS. 632 serving as the "Introduction." Comments on Arnauld's L'art de penser and on the Port Royal Logic. All reasoning consists in interpreting signs; all thought is in signs. System of existential graphs: the simplest system capable of expressing exactly every possible assertion. Definition of "sign."

655. Quest of Quest (QQ)
A. MS., n.p., August 26-September 7, 1910, pp. 1-37.
An inquiry into the question of what makes inquiry successful. On terminology. Requirements for studying philosophy are mastery of Euclid's Elements and mastery of common Greek, medieval Latin, English and German. Definition of "science." The distinction between descriptive and explanatory science. The classification of the sciences. The division of the theoretical sciences into mathematics, philosophy, and idioscopy; the division of philosophy into phaneroscopy, normative science, and metaphysics. Truth and reality. Similarity of CSP's and James's viewpoints accounted for by the common acceptance of cognitionism, a position which derives from their teacher Chauncey Wright. But CSP questions James on the notion of the satisfactory. Remarks by CSP on his special talent and what it is that motivates him.

656. (Q/Q)
A. MS., n.p., September 9-10, 1910, pp. 1-7.
Note: Q/Q is the first revision of QQ (MS. 655). Terminological questions in connection with science and philosophy. The importance of definition for both philosophy and mathematics.

657. Preface (QQ Preface)
A. MS., n.p., September 16, 1910, pp. 1-6.
The author of a new book ought to give an account of himself. CSP writes of the size of his brain "a triffe under" average and his belief that it is unusually convoluted. He acknowledges that he is "ill adapted" for the everyday world, strong in whatever is abstract but lacking in everyday gumption.

658. The Ground Plan of Reason (G)
A. MS., n.p., October 1-3, 1910, pp. 1-6.
Man shares with the lower animals the capacity to feel. How, then, shall we describe feeling? The question is left unanswered.

659. The Rationale of Reason (G')
A. MS., n.p., October 7-22, 1910, pp. 1-41.
Feeling and effort. Faculty psychology and the division of the soul into three parts: feeling, volition, and cognition. Meaning of "faculty" as habitual possibility. Meaning of "person" as any animal that has command of some syntactical language. Problems of terminology. The law of time. Meaning of "real. "

660. On the Foundation of Ampliative Reasoning (AR)
A. MS., n.p., October 24-28, 1910, pp. 1-23, incomplete.
Explicative and ampliative reasoning. Laplace and Mill on induction. Distinction between uniformity (what does happen) and law (what was compelled to happen). Criticism of Laplace's treatment of probability. CSP's views correspond to those of Venn, but derived independently. The notion of "equally possible." (Cf. "objective probability" in Venn, Logic of Chance, 1866.) CSP gives 1864 as the year he arrived at his conception of probability.

661. (AR1)
A. MS., n.p., November 3-13, 1910, pp. 11-15.2, 15-19, 15-111, 110-111, 112-114.
What it means to say that all explicative reasoning is necessary and all necessary reasoning explicative. Logical critic and comments on the Aristotelian logic. Fallibilism and propositions about the meanings of words.

662. (ARM)
A. MS., n.p., November 14-17, 1910, pp. 1-12, 4-7.
Mathematical reasoning illustrated.

663. The Rationale of Reasoning (ARN)
A. MS., n.p., November 17-19g, 1910, pp. 1-17, incomplete; plus p. l of another start.
'The need for stricter rules of nomenclature. Meaning of the word "real." The three modes of reality are would-be's, existents, and can-be's. Berkeley's confusion of "being perceived" with "capable of being perceived." Tendency as denoting a real would-be.

664. The Rationale of Reasoning (AR)
A. MS., n.p., November 22-30, 1910, pp. 1-21, with 7 pp. of variants.
Problems of terminology. Definitions of "breadth" and "depth," both of which presuppose the definition of "proposition." Proposition and assertion. Positive truth and reality. Kant's distinction between knowledge drawn from experience and knowledge that begins in experience. Verbal knowledge.

665. The Rationale of Reasoning (AR)
A. MS., n.p., December 2-3, 1910, pp. 1-5, incomplete.
Conjunction. The origin of the term "premiss," with a reference to Sir James Murray's article in the Oxford Dictionary.

666. (AR)
A. MS., n.p., December 2-3, 1910, pp. 2-3, 5-6.
Earlier draft of MS. 665.

667. The Rationale of Reasoning (AR)
A. MS., n.p., December 8-12, 1910, pp. 1-11, with 3 pp. of variants.
Meaning of "reasoning," with reasoning regarded as essentially an interpretation of signs. Common sense and the soundness of reasoning. Meaning of "knowledge." Nature of probability.

668. (AR)
A. MS., n.p., n.d., pp. 1-18, 20 (possibly of another draft).
Inference and reasoning. Whether any judgment can be absolutely certain. Degrees of belief. Descartes' "Cogito ergo sum." A digression on the failure of people of wealth to support the science of reasoning.

669. Assurance Through Reasoning (A Thr R)
A. MS., n.p., May 25-June 2, 1911, pp. 1-22, with 2 pp. of variants.
Necessary and probable deduction. Existential graphs: syntax and permissions.

670. Assurance Through Reasoning (A Thru R)
A. MS., n.p., June 7-17, 1911, pp. 1-32, with 4 pp. of variants.
Necessary and probable deduction. Syntax of existential graphs. Essential nature of a sign.

671. First Introduction
A. MS., n.p., [c.1911], pp. 1-20; 4-13 of another draft.
The powers of the mind are feeling, causing an action, taking on and abandoning habits. Habit explained in terms of the reality of a general fact about possible conduct; that is, in terms of the reality of would-be's. CSP lists philosophers who are opposed to his realism. Negation and contradiction.

672. Second Essay. On the Essence of Reasoning and its Chief Varieties (II)
A. MS., n.p., [c.1911], pp. 1-6.
These pages were to supersede the 6th article of the Popular Science Monthly series of 1878, of which the first two articles were to appear as Part I and Part II of the "First Essay." These pages concern the false dichotomy of reason and instinct as well as the question whether animals reason. CSP thinks animals do reason, and offers two illustrations.

673. A Sketch of Logical Critic
A. MS., G-c.1911-1, pp. 1-47, with 16 pp. of variants.
Published, in part, as 6.177-184 (pp. 21-44). Omitted: an explanation of logical critic and a definition of "reasoning." The parallel between the exercise of logical self-criticism and the exercise of moral self-criticism. Logical instinct. The triad of normative sciences. The dependence of logic upon ethics, and both upon esthetics. How habits are created. Comte's classification of the sciences. CSP's threefold division of the sciences: heuretic, tagmatic, and practical.

674. A Sketch of Logical Critic
A. MS., n.p., [c.1911], pp. 1-15, with 6 pp. of variants.
On "criticism." Liberal education. Law of habit: CSP's hypothesis, held since 1880, that the law of habit in conjunction with events absolutely uncaused (except by a creative act of God) is all that is required to explain the universe in all its details.

675. A Sketch of Logical Critic
A. MS., n.p., [c.1911], pp. 1-28, 12-20, and 30 pp. of variants.
"Logical critic" explained. Syllogistic recollection; unthought thought, belief and reality; belief as essentially a satisfaction, but not necessarily pleasant. The classification of the sciences and the place of logical critic among the sciences. The normative sciences; esthetics; logic as the science of symbols. The doctrine of signs and the division of signs into icons, indices, and symbols.

676. A Sketch of Logical Critics
A. MS., n.p., [c.1911], pp. 1 -6.
The meaning of "critics" and "logical critics." Definition of "sign."

677. A Sketch of Logical Critic
A. MS., n.p., [C.1911], pp. 1-5, plus 2 pp. of two other attempts to begin the essay.
Explanation of "critic." Art and science. The classification of the sciences.

678. The Art of Reasoning Elucidated
A. MS., n.p., "late in 1910" (p. 26), pp. 1-29, 14-35, with 2 pp. of variants.
Proposal to accomplish seven things in this essay, ranging from a discussion of the different kinds of reasoning to an application of reasoning to the pressing problems of the day. Love of truth as a prerequisite for reasoning well; lover of truth versus lover of knowledge; the three passions for wide knowledge, deep knowledge, and accurate knowledge equated with love of learning, love of knowledge, and love of scientific economy (pp. 1-29). Method of reasoning as man's (as opposed to woman's) way to truth; thinking as "talking" with oneself; the principles of contradiction and excluded middle; real and ratiocinative modality (pp. 14-35).

679. The Art of Reasoning Elucidated
A. MS., n.p., [1910], pp. 1-12, unfinished, with a variant p. 11.
An earlier draft of MS. 678. CSP proposes to do seven things in this essay, but the essay breaks off at this point.

680. Analysis of the Trustworthiness of the Different Kinds of Reasonings
A. MS., n.p., late, pp. 1-26, incomplete, with 18 pp. of variants.
Essay is directed toward boys between the ages of twelve and eighteen who think. The mind-body distinction. The three classes of psychical, physical, and psychophysical. The three elements in all psychical phenomena. Analysis of the state of awareness in terms of its three ingredients. Consciousness of contrast and awareness of change. Triadic distinction of actual fast, may be, and would be. History of the principles of contradiction and excluded middle. Reality of can-be's and would-be's as well as actual facts and existing things. Would-be's related to dispositions and habits.

681. A Study of How to Reason Safely and Efficiently
A. MS., n.p., 1913, pp. 1-47, with a variant p. 7.
Reasoning and sensation. Mixed and unmixed sensations. Esthetic quality attached to reasoning well. The notion of "elegance" in mathematics. Volition and attention. Awareness of acquiring a habit is the third mode of consciousness. What "habit" means. Reasoning as the process of consciously acquiring a belief from previous ones. In defense of trichotomists. CSP records that he does not know and has never inquired whether there is any connection between his own trichotomy and the Divine Trinity, but maintains there is nothing mysterious about his trichotomy. What "real" means. Long footnote on Prantl's Geschichte der Logik im Abendlande.

682. An Essay toward Improving Our Reasoning in Security and in Uberty
A. MS., n.p., [c.1913], pp. 1-53, with 10 pp. of variants.
Defense of final causes. Ratiocination and instinct. CSP is guided by the following maxim: Define all mental characters as far as possible in terms of their outward manifestations. This maxim is roughly equivalent to the rule of pragmatism. It can be said to aid security but not uberty of reasoning. "Yet the maxim of Pragmatism does not bestow a single smile upon beauty, upon moral virtue, or upon abstract truth, the three things that alone raise Humanity above Animality." The science of psychology is of no help in laying the foundations of a sane philosophy of reasoning, and precisely why CSP believes this to be so.

683. [An Essay toward Improving Our Reasoning in Security and in Uberty]
A. MS., n.p., late, pp. 4-38, 12-28, and 16 pp. of variants.
Another version of MS. 682. Mathematical and necessary reasoning. Preference for the word "uberty" over "fruitfulness." The necessity for technical terminology. CSP's ignorance of esthetics, with Schiller's Aesthetische Briefe mentioned as the only book he has read on the subject. But CSP writes of his keen but uncultivated sense of beauty. To illustrate this, he notes works of literature he admires. He also notes that there is little of the artist in him, his own literary style testifying to that. The history of scientific investigation of the problems of ethics. Sir Edward Herbert, Hobbes, Cumberland. The meaning of the word "real." Modalities.

684. A Study of Reasoning in its Security and its Uberty
A. MS., n.p., August 26-31, 1913, pp. 1-13 (p. 8 missing), with 6 pp. of variants.
CSP planned to send copies to Royce, Dewey, Whitehead, and "even to the supercilious Bradley." Reasoning as a branch of endeavor, with an explanation of what is meant by "branch." A long digression on astronomy.

685. The Art of Reasoning Regarded from the Point of View of A. D. 1913. Book I. The Foundations of the Art. Introduction.
A. MS., n.p., 1913, pp. 1-29 (continuous in spite of two p. 28s).
Mathematics is a prerequisite for the study of logic. History of mathematics, especially counting. The notion of "elegance," with true elegance regarded as a variety of economy. The duties and methods of the historian. Was Boethius the author of the geometry and the theological metaphysics attributed to him?

686. Reflexions upon Reasoning
A. MS., n.p., late, pp. 1-9, with a variant p. 7.
"Reality," "state of things," "actuality," and "reasoning" defined. Reality is that aspect of the being of anything which is independent of the thing's being represented. The trustworthiness of immediate knowledge (sense perception) testifies only to this or that single state of things. Reasoning testifies to the truth that lies beyond our ken. CSP wonders what the eternal habits are, beyond those which involve the tridimensionality of space and the general mutability of time. Satisfactory and unsatisfactory feelings.


687. Guessing (guessing)
A. MS., G-c.1907-2, pp. 1-35; plus pp. 2-16 of an earlier draft and 3 pp. of variants.
Published, with deletions, as 7.36-48. The manuscript was published in The Hound and Horn 2 (April-June, 1929) 267-282. Omitted from Collected Papers were pp. 8-22 (for a partial description of which see 7.40n15) and pp. 32-33 (the completion of a personal anecdote). Nature of pure science: questions of pure science handled differently from practical questions. For practical matters cultivate instincts! (Anecdote told in support of this advice.) Decimal and secundal systems of enumeration.

688. Guessing

A. MS., G-c.1907-2, pp. 1-22 (pp. 3-9; 16-18 missing); plus pp. 1-2 (rejected) of another start.
Only the first two sentences of p. 1 published: 7.36n13. This is apparently an earlier draft of MS. 690. Moreover it appears that pp. 3-9 were lifted from here and incorporated in MS. 690. This is not the case, however, with pp. 16-18, which are still missing. Personal anecdote (same as in MS. 687).

689. Surmises About Guessing (Guesses)
A. MS., n.p., n.d., pp. 1-4.
CSP gets only as far as introducing himself to his reader.

690. On the Logic of drawing History from Ancient Documents especially from Testimonies (Logic of History)
A. MS., G-1901-4, pp. 1-263 (continuous although there are no pp. 35, 137, 191), variant p. 15, a typed copy (with marginal corrections by CSP) and a lengthy (6 pp.) "Note on Collections" inserted at p. 52.
Published as 7.164-255, with the exception of 7.182n7, which is from the Lowell Lectures of 1903 (Lecture VIII), and 7.220n18, which is from MS. 691.

691. On the Logic of drawing History from Ancient Documents especially from Testimonies (Logic of History)
A. MS., G-1901-4, 221 pp., fragmentary, with pp. running as high as p. 238. Published, in part, as 7.220n18 (pp. 93-95, with one deletion). CSP added following note: "These pages are to be used in the chapter of the Logic treating Deductive Reasoning. But the theory needs completion." See MS. 1344 for what appears to be an abstract of this logic.

692. The Proper Treatment of Hypotheses: a Preliminary Chapter, toward an Examination of Hume's Argument against Miracles, in its Logic and in its History (Hist. Test.)
A. MS., n.p., 1901, pp. 1-38, 29-40, and 13 pp. of variants.
Opposition to the dualism of reason and instinct. Dogs can reason on occasions, with an example from CSP's experience. Rudimentary sense of logic (logica utens) and the sophisticated sense of logic (logica docens). Attack on modern books on logic. Precepts and hypotheses. The three stages in the life of a hypothesis, each stage governed by entirely different logical principles. Abduction, deduction, and induction.

* 693. Reason's Conscience: A Practical Treatise on the Theory of Discovery; Wherein logic is conceived as Semeiotic
A. MS., six notebooks, n.p., n.d., pp. 2-442 (even numbers mostly, but text is consecutive), including a rewritten section.
Notebook I (pp. 2-80). Purpose of book: improving the reasoning power of students. Pedagogy. Reason and instinct. Interrelations of the branches of science; ladder of the sciences, beginning with the science of discovery and ending with practical science. Notebook II (pp. 82-164). Continues the discussion of the branches of science begun in Notebook I, concentrating on phenomenology, normative science, metaphysics, general physics, and general psychology. The dependence of logic upon the other normative sciences and upon phenomenology and mathematics. The relationship of logic to metaphysics and to psychology. Sound reasoning leads to the maximum of expectation and the minimum of surprise. Notebook III (pp. 166-248). Continues the discussion of sound reasoning specifically and the relationship between logic and psychology generally. The laws of thought. Language and linguistics. The ontological argument. Mathematics and logic; the teaching of mathematics; instructions for understanding Euclidean geometry. Note-book IV (pp. 250-322). Continuation of the instructions for understanding Euclid. Discussion of existential graphs, with a note by CSP that this discussion was rewritten in Notebook V. Notebook V (pp. 278-370). The nature of mathematics. The manner in which two branches of science may support each other. CSP's speculations on the possibility of a phenomenology of esthetics, an esthetics of ethics, an ethics of logic, etc. Notebook VI (pp. 372-442). Continuation of the discussion of the usefulness of one science to another. The descriptive and classificatory sciences. The problem of knowledge: perceptual knowledge; individuality and classes; unity, singularity, and individuality distinguished; expectations.

694. The Rules of Right Reasoning (Rules of RR or RRR)
A. MS., n.p., n.d., pp. 1-5.
Introductory. Study of the right methods of reasoning has occupied CSP for forty-five years. Notes deficiencies as a writer. His hopes of writing a great work on logic have given way to his hope of writing a shorter, less perfect version. CSP offers his plan of simplification.

695. A Practical Treatise on Logic and Methodology
A. MS., n.p., n.d., 18 pp. of several attempts, none of which go beyond a few pages.
Purpose: establishing maxims for estimating validity and strength of arguments. Explanation of the use of the terms "logic" and "methodology." The function of reason. Genuine doubt and genuine investigation.

696. Practical Maxims of Logic
A. MS., n.p., n.d., 27 pp., of which 4 pp. are in Zina Fay Peirce's hand.
Deduction, induction, and hypothesis as practical considerations. Beware of the syllogism: everything can be explained, with the syllogism merely making our knowledge more distinct. With regard to the ontological argument, every definition implies existence of its object. Random sampling.

697. Lessons on Practical Logic
A. MS., n.p., n.d., 5 pp.
Concerning the definition of "logic." The investigation of consequences constitutes logic, with material and formal consequences distinguished. Suggestions of possible topics for a course in practical logic.

698. [Maxims of Reasoning]
A. MS., n.p., n.d., pp. 2-3, 5.
Maxim III: "The object of reasoning is to settle questions." Maxim IV: "Things are not just as we choose to think them."

699. [Logical and Mathematical Exercises]
A. MS. and TS., n.p., n.d., 13 pp.
Illustrations of logical doctrine.

700. [Quiz]
A. MS., n.p., n.d., 4 pp.

701. [Logical Puzzles]
A. MS., n.p., n.d., 4 pp.

702 [Logical Exercises]
A. MS., n.p., n.d., 6 pp.

703. Note (Notes on Art. III)
A. MS., G-1910-2, August 11-15, pp. 1-30 (with p. 5 missing); 6, 8-10 of another draft; and pp. 1-2 ("Notes to CSP's Third Paper in the Pop. Sci. Monthly, 1878, March").
Published in entirety as 2.661-668 and as 2.645n1. Article III refers to the third in the Popular Science Monthly series of 1877-78.

704. Notes to be added to C. S. Peirce's Third Article in Pop. Sc. Monthly (Notes No III)
A. MS., n.p., n.d., pp. 1-3.
This is a footnote to be inserted on p. 604, line 3, after the word "evident." General laws in chemistry; Vant Hoff's general law of mass-action.

705. Notes on the List of Postulates of Dr. Huntington's #2 (On Postulates)
A. MS., G-c.1904-1, pp. 1-11, 10-12, 10-11.
Published as 4.324-330 (pp. 1-11).

706. [The Concept of Probability]
A. MS., n.p., January 23-31, 1909, pp. 1-31, with 3 pp. of variants.
Remarks on the history of the concept of probability, noting incidentally that the Greeks had no idea of such a concept. Pascal's method of treating probability. Science is raised to a higher level by the "Doctrine of Chances."

* 707. Note to Sylvester's Papers Vol. I p. 92
A. MS., n.p., n.d., 1 folded sheet.
System of dyadic monosynthemes of the 6th order.

708. Reply to Mr. Kempe (K)
A. MS., n.p., n.d., pp. 1-9, 5-7, and 5 pp. of another draft.
This is a reply to a short article in the Monist of 1897 by A. B. Kempe, which was itself, in part at least, a reply to CSP's article in the Monist (January 1897). See 3.468.

709. Note on Kempe's Paper in Vol. XXI of the Proceedings of the London Mathematical Society
A. MS., n.p., n.d., pp 1-6, plus 3 pp.
See MSS. 710-714 for further discussion of Kempe's paper.

710. Notes on Kempe's Paper
A. MS., n.p., n.d., pp. 1-2, plus 7 pp.

711 . Notes on Kempe's Paper
A. MS., n.p., n.d., 4 pp.

712. (Kempe)
A. MS., n.p., n.d., 1 p.

713. (Kempe)
A. MS., n.p., n.d., 2 pp.
In praise of Kempe's mathematical powers and native instinct for doing logic, but critical of "his sad want of training" in logic. Specific criticism noted.

714. Notes on Kempe's Paper on Mathematical Forms
A. MS., n.p., January 15, 1889, 12 pp.

715. Kempe Translated into English
A. MS., n.p., n.d., 1 p.

716. [Fragment on Thirdness and Generality]
A. MS., G-c.1895-3, 3 pp.
Published in entirety as 1.340-342.

*717 Chapter II. The Categories
A. MS., n.p., n.d., 8 pp. (text is consecutive); plus 24 pp. (fragmentary).
Probably from the period of the Grand Logic. Assertions about systems of more than three subjects can be reduced to triadic assertions at most. The whole endeavor to deny the irreducibility of triadic facts is termed "nominalism." The realism-nominalism controversy. Nature of signs. Categoriology. Continuity and continuous series.

718. [On Continuous Series]
A. MS., n.p., n.d., 5 pp.
An attempt to show that the whole series of numbers, rational and irrational, does not constitute a continuous series.

719. Chapter I. Certain Fundamental Conceptions
A. MS., n.p., n.d., 5 pp.
Use of term(s) ens (entia). Recourse to Scholastic usage. The first two principles of logic: (1) something or other is true of every ens, and (2) for everything which is true of an ens, something must be true of a pair of entia of which that is one.

720. Logic. Chapter I.
A. MS., n.p., n.d., 9 pp.
The end of logic is to form a table of categories. Proper method of deducing the categories. Qualities, relations, representations distinguished.

721. Chapter I. One, Two, Three
A. MS., n.p., n.d., pp. 1-5, plus 7 pp.
Logic begins with the analysis of the meaning of certain words of which the first is "is" (copula). Ens (entia) in Scholasticism. CSP then turns to the conceptions of one, two, and three before tackling the conception of independent being, but he gets only as far as a consideration of quality.

722. Chapter I. Fundamental Notions
A. MS., n.p., n.d., 2 pp.
Ens (entia) given the foremost place among logical terms. Its Scholastic usage.

723. A System of Logic. Chapter I. Syllogism
A. MS., n.p., n.d., pp. 1-6.
The historic origin of logic is the desire to test inferences. One should begin the study of logic with the syllogism; terms and propositions should be studied afterwards. Remarks on Aristotle's definition of "logic" and on Duns Scotus' views of logic.

724. Logic. Chapter I. Terms
A. MS., n.p., n.d., 4 pp. and 2 pp. of an earlier draft.
Representations, symbols, and logic. Two terms are related to each other with regard to extension, comprehension, and implication.

725. On Logical Extension and Comprehension
A. MS., notebook, n.p., n.d.
CSP comments on his own article of November 13, 1867 (G-1867-1e) and adds a 6th section entitled "Of Natural Classification," an attempt to say precisely what a natural class is.

726. An Unpsychological View of Logic to which are appended some applications of the theory to Psychology and other subjects
A. MS., n.p., [1865?], 76 pp.
An early work primarily on the intension and extension of terms which was superseded by "Upon Logical Comprehension and Extension" (G-1867-1e). Definition of "logic." Connotation, denotation, and information. The relationship of comprehension, extension, and implication summed up in the formula: Extension x comprehension = implication. Forms of induction and hypothesis.

727. [Notes on Intension and Extension]
A. MS., n.p., n.d., 2 pp.

728. Chapter 2. First Division of Symbols in Logic
A. MS., n.p., n.d., 2 pp.
Logic is a classificatory science. Its study should be preceded by a study of the science of classification.

729. Chapter II.
A. MS., n.p., n.d., 4 pp.
Logic as a classificatory science. Kinds of representation.

730. Logic. Chapter 3.
A. MS., n.p., n.d., 4 pp.
Symbols regarded as terms, propositions, and arguments.

731. Chapter II. Extension, Comprehension, Implication
A. MS., n.p., n.d., 9 pp., plus 4 pp. of an earlier attempt.

732. lntroduction
A. MS., n.p., n.d., pp. 1-16.
Impressions; precision, discrimination, dissociation; substance; accident; Being; quality, relation, representation; ground, correlate, interpretant; formal objects. A note concerning a nameless philosopher of the 12th century appears on the verso of one of the pages.

733. Logic. Chapter I
A. MS., n.p., n.d., 3 pp.
Every conception is a hypothesis (supposition). Abstraction as separation in conception as opposed to separation in fact and in imagination. Conception of Being: Being distinguished from Dasein.

734. Logic. Chapter 2. Formal Logic
A. MS., n.p., n.d., 53 pp.
Explanation of some of the basic terms of formal logic. The objects of logic are symbols; the business of logic is the classification of symbols. Logic itself is a symbol. Symbols: terms, propositions, and arguments. The syllogism.

735. Logic. The Theory of Reasoning. Part I. Exact Logic. Introduction. What is Logic (EL) A. MS., n.p., n.d., pp. 1-2, 1-5, 1-13, with a title page and a table of contents. Logic is the theory of reasoning and, as such, it is not a branch of psychology (pp. 1-2). Reasoning and common sense (reasoning from the initial propositions of common sense); the relationship between hope and truth (pp. 1-5). A sect of philosophy concerned with deducing the rules of reasoning by mathematics (the achievements of this sect include CSP's contribution of the logic of continuity); Mill's logic; Sigwart and Kant; Hegel's importance to German philosophy; reasoning and signs (pp. 1-13).

736. Qualitative Logic
A. MS., G-undated-11 [1893?], 1 p. (table of contents); pp. 1-11 (preface); pp. 1-10, 2-4, 1-8 ("Chapter I. The Association of Ideas"); pp. 1-6, 1-3 ("Chapter II. The Simple Consequences"); pp. 1-11, 1-8, and a variant p. 6 ("Chapter III. The Modus Ponens"); pp. 1-48, with 24 pp. of variants ("Chapter IV. The Syllogism" and "The Traditional Syllogistic"); pp. 1-8 ("Chapter V. The Dilemma"); pp. 1-5 ("Chapter V. Dilemmatic Reasoning"); pp. 1-6, 1-2 ("Chapter VI. Logical Extension and Comprehension"); pp. 1-22, with 60 pp. of variants ("Chapter VI. The Logical Algebra of Boole"); 1 p. ("Chapter VI. Logical Algebra and Logic of Relatives"); plus 35 pp. of fragments.
Published, in part, as 7.451-457 (Chapter 1, pp. 1-10) and 7.458-462 (Chapter II, pp. 1-5).

737. Memoir #4. Algebra of Copula
A. MS., n.p., n.d., 9 pp.

738. [On the Quantified Predicate]
A. MS., n.p., n.d., 4 pp.
CSP rejects the thesis that the copula of a proposition expresses primarily the identity relation, noting arguments in its favor, especially Hamilton's.

*739. [Thought and Feeling]
A. MS., n.p., n.d., pp. 30-32.
These pages may be part of a proposed book in logic. Division of the operations of the understanding into simple apprehension, judgment, and reasoning. Distinction between objective and subjective intensity of feeling. Combination of feelings which, in some cases, is strongly suggestive of thought.

740. Appendix No. 2
A. MS., n.p., n.d., 43 pp.
The hypothetic and sensational character of simple conceptions: The Kantian position on space and time is analyzed. Difference in time is a quantitative, continuous, commutative ground of disquiparance; difference in space is a quantitative, continuous, noncommutative ground of disquiparance.

741. [Sheets from a Notebook on Logic]
A. MS., n.p., [c.1860-c.1867], 75 pp.
It is possible to distinguish the following: "On the Figures and Moods of Logic" (c.1860): induction as the middle road between a priori and a posteriori reasoning; the figures of the different kinds of inferences (7 pp. of an early draft of a work on the Aristotelian syllogism). "Induction": Aristotle's views on induction; objection to Hamilton's "logical" induction; the denotation of subjects and the connotation of predicates (Sept. 1864, 2 pp.). "Consideration of the 3rd Argument in favor of the [quantification of the] predicate" (1867, 1 p.). "On the Conversion of Quantity" (c.1867, 2 pp.). "Further Arguments for a Quantified Predicate considered" (c.1867, 1 p.). "Analogy between Logic and Algebra" (c.1865, 1 p.). "Problem. To apply algebra to logic": a numerical interpretation of Boolean concepts, e.g., a + b = 2 S a and b are two facts (c.1866, 4 pp.). "Propositions of Disquiparance" (c.1866, 2 pp.). "Doctrine of Conversion" (C.1860, 4 pp.). "Quality is the only Quantity belonging to the Predicate": the distinction between extension and intension (c.1866, 2 pp. and 4 pp.). "Extension, Intension, etc." (c.1867, 8 pp.). "The Course of Expression": the concrete expression of an idea requires a mode of presentation (c.1867, 2 pp.). "Quantity of the Figures" (c.1867, 2 pp.). "Notation: Considerations of the Advantages of Sir W. H.'s Analytic intended to show that mine has the same" (c.1867, 4 pp.). "Associative Principle" (c.1867, 11 pp., of which seven are in the hand of Zina Fay Peirce). The remainder are fragments and include, among other topics, notes on the syllogism and on the relation of extension, intension, and information.

742. Preliminary Sketch of Logic
A. MS., small notebook, n.p., [c.1865].
Argument; leading principle; copula; term.

743. The Rules of Logic logically Deduced
A. MS., n.p., June 23, 1860, 8 pp.
Propositions collate conceptions. Collation is comparison, and a conclusion is a comparison drawn from two comparisons. Problematical, apodictic, and assertive propositions. The application of geometry to logical doctrines.

744. Of the Distinction between a priori and a posteriori
A. MS., n.p., n.d., 10 pp., plus a folded page with the title: "Distinction between a priori and a posteriori."
Arguments in the first, second, and third figures are respectively a priori, a posteriori, and inductive. Table showing logical character of every mood. Logically a priori conclusions are universal, affirmative, categorical, apodictic. Logically inductive conclusions are particular, infinite, hypothetical, assertorial. Logically a posteriori conclusions are singular, negative, disjunctive, problematical .

745. [Plan for Sixty Lectures on Logic]
A. MS., n.p., n.d., pp. 1-25, with 17 pp. of other attempts to state the substance of the lectures.
Brief descriptions of the subjects of each lecture. The subject matter ranges widely from the physiological and psychological bases of logic (first lecture) to anthropomorphic science, physiognomy, art, and natural theology (sixtieth lecture).

746. [Introductory Remarks to a Course in Logic]
A. MS., n.p., n.d., 9 pp.
Historical notes on Aristotle and the Stoics. CSP attempts to answer the question: Is logic a science? His conclusion is that logic is the science that analyzes method.

747. [Fragments on Logic]
A. MS., n.p., n.d., 46 pp.
These fragments may belong to the Johns Hopkins period. Among the 46 pp. are 7 pp. on the logic of relatives, one page of which reads: "Chapter IV. The Logic of Plural Relatives." The remaining pages concern the derivation of the word "logic," kinds of inferences, statistical deductions, probability.

*748. Logic: and the Methods of Science. Book I. Formal Logic. Chapter I. The Modus Ponens TS. (corrected), n.p., n.d., pp. 1-2 and 14 pp. of several drafts.

748a. Logic. Chapter I. Of thinking as Cerebration
TS. (corrected), n.p., n.d., pp. 1, 1-7, 1-9, 1-2, 3, 3-6.

748b. [Outline and First Chapter of a Book on Probability]
TS. (corrected), n.p., n.d., 1 p. ("Plan and Object of this Work"), 1 p. ("Table of Contents"), pp. 1-8 ("Part I. Descriptions. Chapter I. The Question in Probability").

748c. [Draft of "The Observational Element in Mathematics"]
TS., n.p., n.d., pp. 4-5 and 3 unnumbered pages.

748d. The Settlement of Opinion
TS., n.p., n.d., pp. 9-10, variant of 5.377.

749. [What logic is]
A. MS., n.p., n.d., 10 pp.
Is logic a science or an art? Does logic have a practical aim? If so, what is that aim? The various schools of logic (transcendental, seientific, etc.).

750. Logic I.
A. MS., n.p., n.d., pp. 1-2, incomplete.
The essence of the distinction between good and bad reasoning does not lie, as Sigwart believes, in a difference of feeling. It is a matter of fact.

751. [Lecture on Logic]
A. MS., n.p., n.d., pp. 1-4.
Part of a lecture series. The independence of logic from psychology. Logic and artificial languages. Deduction, induction, and retroduction.

752. [Reasoning]
A. MS., n.p., March 15, 1914, 3 pp. and 1 p.
One of the last of CSP's manuscripts, it deals with the three orders of reasoning (deduction, induction, and retroduction) and with the limits of CSP's confidence in science.

753. [Reasoning] A. MS., n.p., n.d., pp. 3-7 and a variant p. 5.
Draft of G-1907-1. Presumably for a lecture on the three kinds of reasoning. Examples of induction. Lutoslawski's and CSP's researches on Plato.

754. Second Talk to the Phil. Club [and] Second Talk. On Deduction
A. MS., n.p., April 12, 1907, 2 folded sheets.
On the three kinds of reasoning (deduction, induction, retroduction). Method for the discovery of methods. Corollarial reasoning. Hypotheses of pure mathematics. The adventitious character of CSP's logical gift.

755. [On the Three Kinds of Reasoning]
A. MS., n.p., n.d., pp. 1-19, 9-23, with variants.
Drafts of beginning of CSP's "Little Book on Religion," c.1911: natural gift of understanding, common sense and self-deception, belief and conduct.

756. Retroduction (Retr)
A. MS., n.p., late, pp. 1-9, 1-5.
The three kinds or stages of inquiry illustrated.

757. What is Reasoning
A. MS., n.p., n.d., 14 pp.; plus 2 copies of 2 pp. each (not in CSP's hand) and a TS. of 7 pp. An elementary exposition of necessary and probable reasoning.

758. (Aristotle 9, Aristotle 10)
A. MS., n.p., n.d., 4 pp., incomplete.
A lecture on inference, with all elementary inferences divided into three classes. Is the division into three classes natural?
759. (B)
A. MS., n.p., n.d., pp. 1-3.
On the modes of necessary inference.

760. [Necessary Reasoning]
A. MS., n.p., n.d., 4 pp.

761. Examples of Probable Reasoning
A. MS., n.p., n.d., 1 p.
Possibly a test question. The reader is asked to draw a conclusion (probable) from a set of four facts presented to him.

762. [Plan for a Work on Probability]
A. MS., n.p., n.d., 1 p. (plan); 1 p. of what may be the start of the proposed work; pp. 7-15 (not in CSP's hand).

763. The Doctrine of Chances
A. MS., n.p., n.d., pp. 1-3; 1-2 (New).
Introductory comments only. Ancient inquiries into the nature of probability.

* 764. [Probability and Induction]
A. MS., n.p., n.d., 99 pp.
The topics of these fragments range widely from CSP's comment on his habit of thinking in the syntax of existential graphs to discussions of probability, orders of induction (crude, quantitative, qualitative), the divisions of deduction as corollarial and theorematic; introduction of the term "adduction," with a note that the adductions of Socrates were of a crude order. Also notes on the history of logic (Aristotle, Bacon, English logicians) and reflections on the meaning of "pragmatism," and its connection with signs and habits. In regard to the origins of the word "pragmatism," CSP writes: "It was about 1870 - I don't think it could have been as late as 1872 - that I invented the word...."

765. Lecture II
A. MS., n.p., n.d., 1 folded sheet.
On the theory of induction. Hamilton and Mansel. Aristotle's notion of induction .

766. Synopsis of the Discussion of the Ground of Induction (S)
A. MS., n.p., n.d., pp. 1-3, incomplete.
Criticism of the view that the probability of inductive conclusions is calculated by inverse probabilities. CSP takes the position that "in inductive reasoning the fact stated in the conclusion does not follow from the facts stated in the premises with any definite probability, but that from the manner in which the facts stated in the premises have come to our knowledge it follows that in assigning to a certain ratio of frequency the value concluded we shall be following a rule of conduct which must operate to our advantage in the long run."
767. [Fragments on Induction and Abduction]
A. MS., n.p., n.d., 5 pp.

768. Statistical Deduction
A. MS., n.p., n.d., 1 p.

769. Logic of Science
A. MS., n.p., n.d., 24 pp. of several starts.
Definition of "logic." Marks of the 1st, 2nd, and 3rd orders. The mark of representation is of the 3rd order.

770. The Logic of Science
A. MS., n.p., n.d., pp. 1-6, with variants.
The meaning of "logic of science." Absurdity of a common sense logic, with accompanying remarks on common sense in general. Intimate connection between reasoning and morality. On the richness of various languages, with special praise for Greek.

771. Essays on the Rationale of Science
A. MS., n.p., n.d., pp. 1-3; 1-3; 1-3, and a variant p. 2 and an unnumbered page. Autobiographical note concerning the publication of the Popular Science articles of 1877-78.

772. [Physical Laws]
A. MS., n.p., [c.1873], pp- 2-7.
Draft of N-1873-1. Scientific theories and inductive processes. The way in which physicists provide definitions in terms of mass, space, and time. Law of nature is a general relation connecting measures of different quantities.

773. Third Lecture on Methodeutic
A. MS., n.p., n.d., 1 folded sheet.
CSP opens his lecture with an apology for the lecture of the previous evening and with a proof he failed to provide on that occasion. Theoric deduction as creative (its object is not an existing thing, but an ens rationis which is just as real). Object and interpretant of a sign. Three grades of induction.

774. Ideas, Stray or Stolen, about scientific writing. No. 1 (Rh. Sc.)
A. MS., n.p., n.d., pp. 1-16.
Semeiotics. Speculative rhetoric. A universal art of rhetoric acknowledged as an ens in posse, Ordinary rhetoric should be modified by way of special studies. These studies yield the various rhetorics of fine arts, speech and language, science. The rhetoric of science is subdivided into rhetorics of communication of discoveries, scientific digests, and applications of science for special purposes.

775. Jottings on the Language of Science. No. 1 or Ideas, stray or stolen, about scientific writing. No. 1 (Rh. Sc.)
A. MS., n.p., n.d., pp. 1-14.
Earlier draft of MS. 774.

776. The Rhetoric of Scientific Communications (Rhetoric of Sci or Rh of Sci)
A. MS., n.p., n.d., pp. 1-6, 4-5.
The problem of communicating discoveries. Scientific terminology. The best types of titles for scientific papers.

777. Plan of an Essay on the Rhetoric of Scientific Communication in two parts of ten of these Ms. pages each. Part I. General. Part II. Special
A. MS., n.p., n.d., 6 pp.
Semeiotics. Universal rhetoric.

778. [Late Fragments on Logic and Science]
A. MS., n.p., [c. 1909], pp. 5-15.
From a rambling lecture touching on the kinds of reasoning, the classification of the sciences, nominalism and realism in medieval logic, and the lecturer's scorn for contemporary philosophy and ". . . the stupid and utterly antiscientific doctrine that a law of nature is nothing but a fabrication of the human mind."

779. [Syllogism]
A. MS., n.p., n.d., 8 pp. of fragments.
Aristotle and the history of logic.

780. Table of Syllogisms
A. MS., n.p., n.d., 3 pp. (not in CSP's hand, with the exception of a single correction).
MSS. 780-782 may be parts of an examination.

781. Classification of Universals
A. MS., n.p., n.d., 2 pp. (not in CSP's hand).

782. Table of Contraposition
A. MS., n.p., n.d., 1 p. (not in CSP's hand)

783 [On the Syllogism]
A. MS., n.p., n.d., 4 pp.
Possibly an early draft of "Classification of Arguments."

784. Two Fallacies
A. MS., n.p., April 20, 1901, pp. 1-5
CSP notes that Mrs. Ladd-Franklin's method of testing syllogisms, based on the inconsistency of three propositions, is very similar to the method he used for the moods of the fourth figure (but which he rejected) in his paper: "On the Natural Classification of Arguments" (see G-1867-1b).

785. Notes (to 1867 paper Vol. 3)
A. MS., n.p., n.d., 25 pp.
See G-1867-1a.

786. Notes on Mrs. Franklin's Article "Syllogism" (Syllogism)
A. MS., n .p ., n.d., pp. 1-18.

787. That Categorical and Hypothetical Propositions are one in essence, with some connected matters
A. MS., G-c.1895-1, pp. 1-49 (pp. 6-9 missing).
Published in Collected Papers in the following order: 2.332-339, 2.278-280, 1.564-567 (c.1899), 2-340-356.

788. Propositions of the 0 order, Propositions of the 1st order, Syllogisms of 0-0 order, Syllogisms of the 0-1 order, Syllogisms of the 1-1 order
A. MS., n.p., n.d., pp. 1-6.

789. [Elements of a Proposition]
A. MS., n.p., n.d., 6 pp. and 6 pp. (Universe).
"Universe" of a proposition is defined as "a series of possibilities to which the proposition refers but whose limits cannot be described in general terms but can only be indicated in some other way." A proposition may relate to several such universes.

790. [Fragment on Hypothetical Propositions]
A. MS., G-undated- 17, 1 p.
Published in entirety as 8.380n4,

791. #5 Analysis of the Proposition
A. MS., n.p., n.d., 1 p.

792. On the Logical Nature of the Proposition (Dicisign)
A. MS., n.p., n.d., pp. 1-2, with a rejected p. 2.
Notes confusion of proposition with statement, assertion, physical act of judging, and an act of assent. CSP proposes to state his own theory of propositions, and then he launches into a discussion of signs.

793. [On Signs]
A. MS., n.p., n.d., pp. 1-4, 10-14; plus 9 pp. of variants and 1 p. (fragment).
An attempt to define "sign" as a medium for the communication of form. Sign as essentially triadic. Application of existential graphs to signs. Speculative grammar, critic, and methodeutic. On p. 14 verso is the beginning of a letter to "Professor James."

794. Sections of Roget's Thesaurus containing words meaning signs
A. MS., n.p., n.d., 1p.

795. [Classification of Signs on the Basis of Idea, Token, and Type]
A. MS., n.p., n.d., 1 p.

796. The Art of Reasoning. Chapter I. What is a Sign?
A. MS., n.p., n.d., 2 pp.
Introduction of terms: quality, relations, focus, ratio, a relate, reagents, terms, signification, representamen.

797. [Fragments on Signs]
A. MS., n.p., n.d., 9 pp. (but not all from the same work).

798. [On Signs]
A. MS., G-c.1897-3, 5 pp.
Published as 2.227-229 and 2.444n1.

799. [Ten Classes of Signs]
A. MS., n.p., n.d., 3 pp.

800. P of L
A. MS., n.p., n.d., pp. 2-6, 10; plus l p.
On the classification of signs.

801. Logic: Regarded as a Study of the General Nature of Signs (Logic)
A. MS., n.p., n.d., pp. 1-4.
The transition from feeling to knowing. Definition of "sign." Calculations on the verso of one of the pages.

* 802. Teleological Logic
A. MS., n.p., begun May 14, 1865, 4 pp., incomplete.
Logic as the semeiotic science of representations. Division of the sciences into science of things, representations, and forms. Kinds of representations: signs, symbols, and copies.

803. [Logic and Signs]
A. MS., n.p., n.d., pp. 1-5.

* 804. [Assertion and Signs]
A. MS., n.p., n.d., pp. 22, 24, 29, 33.

* 805. [The Essential Nature of Assertions]
A. MS., n.p., n.d., pp. 18-20

806. Of Modality
A. MS., n.p., n.d., 3 pp.
The verso of one of the pages contains a chart, dated July 12, 1908, and labelled "Divisions of Signs."

* 807. [Necessary Modality]
A. MS., n.p., n.d., pp. 16-20.
Religious instinct and the evolution of the universe. Note on the relation of mathematical abilities and music.

808. Formal Division(s) of Dyadic Relations
A. MS., n.p., n.d., 5 pp.

809. #12. Division of Formal Science
A. MS., n.p., n.d., 5 pp.
The nine prescindible references and the nine formal sciences.

810. [On the Formal Principles of Deductive Logic]
A. MS., n.p., n.d., 4 pp. and 4 pp.
An attempt to recapitulate the principles of the logic of relatives. The nature of a sign, or representation.

811. [Printed Pages of "On the Natural Classification of Arguments"]
Printed pages (annotated), G-1867-1b (1893).
These pages from The Proceedings of the American Academy (1867) contain CSP's revisions of 1893. See sup(1)G1867-1b. Published, again, as 2.461-516, with the revisions of 1893.

* 812. Logico-Mathematical Glosses
A. MS., n.p., n.d., 8 pp. and pp. 8-9.
Boolean algebra. Sundry misconceptions about mathematical logic
(pp. 8-9).

813. [Logic and Mathematics]
A. MS., n.p., n.d., 6 pp.
Material on existential graphs.

814. Achilles and the Tortoise
A. MS., n.p., n.d., pp. 1-6.

815. [Achilles and the Tortoise]
A. MS., n.p., n.d., pp. 2-6.

816. [On Five Grades of Originality in Logic, with Illustrations from the History of Logic]
A. MS., n.p., n.d., 6 pp.
Comments on Royce as logician and metaphysician, especially in connection with Royce's memoir, "The Relation of the Principles of Logic to the Foundations of Geometry."

817. [Various Fragments on Indicative Words, Hypothetical Propositions, Truth and Satisfaction]
A. MS., n.p., n.d., 4 pp.

818. Mr. Bertrand Russell's Paradox
A. MS., n.p., late, 5 pp., unfinished.

819. The Conception of Infinity
A. MS., n p., [c-1880], 5 pp.
De Morgan's syllogism of transposed quantity, and the inappropriateness of one of De Morgan's examples. Fermatian inference and the collections to which it does and does not apply.

820. [Fermatian Inference]
A. MS., n.p., n.d., pp. 1-6.

821. Some Unmanageable Problems
A. MS., n.p., n.d., 7 pp.
Notes on Cantor's "Beitro/ooge zur Begrundung der transfiniten Mengenlehre" (Mathematische Annalen of 1895).

822. [Hamilton and Mansel]
A. MS., n.p., n.d., 2 pp.
Laws of reasoning. Mansel's definitions of "absolute" and "infinite."

823. [Critic of Arguments]
A. MS., n.p., n.d., 4 pp., consecutive but incomplete.
An evaluation (and appreciation) of Benjamin Peirce's powers of analysis. An examination of Mansel's views on logic.

824. Triadic Monosynthemes of Six Monads
A. MS., notebook, n.p., n.d.
The notebook also contains a list of names (of students?) and an estimate of their abilities, but this part of the notebook is not in CSP's hand. Drafts of two letters which were in the notebook have been removed and placed with CSP's correspondence. One of these drafts was to B. E. Smith and the other to F. C. S. Schiller.

825. (FRL)
A. MS., G-c.1899-1, 3 pp.
Published in entirety as 1.135-40.

826. Some Reveries of a Dotard
A. MS., n.p., late, pp. 1-5.
Logic as the science which distinguishes bad from sound reasoning. The sense of obligation in reasoning. Reflections on psychophysics. Fallibilism.

827. [Logic and the Doctrine of "Anti-cock-sure-ism"]
A. MS., n.p., n.d., 4 pp.
Inexactitude of physical laws, e.g., law of gravitation.

828. Logic (Li)
A. MS., n.p., November 2, 1910, pp. 1-3.
An analysis of doubt as neither ignorance nor consciousness of ignorance. Doubt is treated as an emotion.

829. [Absolute Certainty]
A. MS., n.p., n.d., 2 sheets, numbered 2 and 3, incomplete.
CSP's inability to discover a single truth which seems free of doubt. Discussion of the propositions "I feel a prick" and "Twice two is four."

830. [Reasoning and Belief]
A. MS., n.p., n.d., 2 pp., incomplete; plus 1 p. of a rejected draft.

831. [Reasoning and Instinct]
A. MS., n.p., n.d., pp. 2-29, incomplete.
The fine gradations between subconscious or instinctive mind and conscious, controlled reason. Logical machines are not strictly reasoning machines because they lack the ability of self-criticism and the ability to correct defects which may crop up. Three kinds of reasoning: inductive, deductive, hypothetical. Quasi-inferences.

832. [Reason and Instinct]
A. MS., n.p., n.d., 3 pp.
Reason as inferior to instinct. Comments on the work of Zeller and other German logicians and historical philosophers.

833. [Veracity]
A. MS., n.p., n.d., 2 pp.
Signs, truth, and veracity. Perfect veracity distinct from cognizable veracity.

834. [First, Second, and Third Degrees of Knowledge]
A. MS, n.p., n.d., 1 p.

835. [Three Grades of Clearness of Thought]
A. MS., n.p., n.d., pp. 9-17, incomplete.
Absurdity of the doctrine of simple concepts.

836. [Fragments on the Normative Sciences]
A. MS., n.p., n.d., 5 pp.

837. [Various Topics in Logic]
A. MS., n.p., n.d., 27 pp.
Necessary reasoning, hypothesis, the syllogism, the logic of relatives, and the relationship between logic and evolution.

838. [Fragments on the Justification of Reasoning]
A. MS., n.p., late, 9 pp.
The fragments, all concerned with the same problem, are not from the same work. Two of the fragments are dated: April 10, 1911 and February 22, 1912.

* 839. [Fragments]
A. MS., n.p., n.d., 199 pp.
Existential graphs, the logic of relatives, logical critic, theory of signs, hypothesis and induction, belief and reasoning, generalization, rationale of science, and classification are some of the topics found here. One page is dated September 22, 1860; the remainder are undated and apparently cover several periods of CSP's career.

840. [Fragment]
A. MS., n.p., n.d., 1 p.
"Logic is a sort of tree of knowledge of good and evil which costs the loss of paradise to him who tastes of its fruit."