^{page 17 note 2} Cf. Couturat, L., La Logique de Leibniz (Paris, 1901), pp. 196, 202–3Google Scholar, with texts there cited. For a more recent version of this criticism, cf. Peirce, C. S., Collected Papers, 5, 391Google Scholar.

^{page 17 note 3} Vae Obj., VII, 278–9. Cf. ibid., 318. References are to the volume and page of Œuvres de Descartes, ed. Adam-Tannery.

^{page 18 note 1} Vae Resp., VII, 361–2. (Italics here and in all other quotations are mine.) An anonymous exponent of Gassendi took up the debate at this point, “denying” that Descartes had set forth a method for distinguishing the really from the apparently clear and distinct (X*** to Descartes, July 1641; III, 402). Unfortunately, however, his examples of men firmly convinced of the clearness and distinctness of their perceptions, and nevertheless in contradiction to one another, were all taken from theological controversy, so that Descartes was able to say in rebuttal merely that “reply to them would be very easy for one who distinguishes the light of faith from the natural light, and sets the former before the latter” (to X***, Aug. 1641; III, 426).

^{page 18 note 2} Couturat, op. cit., p. 100, nn. 2 and 3; p. 203, n. 2.

^{page 18 note 3} Disc. IV, VI, 33.

^{page 18 note 4} Vae Resp., VII, 379.

^{page 18 note 5} Reg. X, X, 405–6.

^{page 18 note 6} IIae Resp., VTI, 156.

^{page 19 note 1} IIae Resp., VII, 155–6.

^{page 19 note 2} Cf. Disc. II, VI, 18. IIIae, IIae Resp., VII, 146, 192. Reg. II, X, 363. To Regius, 24 May, 1640; 111, 65. To X***, Aug. 1641; III, 430–1. Princ. I, 50, 68. Notae in Prog., VIII (2), 352.

^{page 19 note 3} VIIae Resp., VII, 461–2.

^{page 19 note 4} Ibid., 511.

^{page 19 note 5} Reg. II, III, IV, XII, X, 365, 369, 372. 429.

^{page 19 note 6} Reg. IV. XII, XIV, X, 372, 428, 439–40. 451.

^{page 19 note 7} “… ostendo me nomen ideae sumere pro omni eo quod immediate a mente percipitur.” IIIae Resp., VII, 181.

^{page 19 note 8} Med. III, VII, 40 ff. Cf. ibid., 37: “Quaedam ex his (cogitationibus) tanquam rerum imagines sunt, quibus solis proprie convenit ideae nomen.”

^{page 20 note 1} IVae Resp., VII 232.

^{page 20 note 2} To Gibieuf, 10 Jan. 1642; III, 476.

^{page 20 note 3} Princ. I, 45.

^{page 21 note 1} IVae Resp., VII, 246.

^{page 21 note 2} To Mersenne, July 1641; III, 392–3.

^{page 21 note 3} IIae Resp., Def. II, VII, 160.

^{page 21 note 4} Nouv. Ess., II, i, 1.

^{page 22 note 1} Essay concerning Human Understanding, II, xxix, 5–6. Nouv. Ess., ad loc. For Kant's echo of the same difficulty, cf. Krit. d. r. V., Paralog., B 414–15 Anm.

^{page 22 note 2} Princ. I, 68. Cf. Med. III, VII, 35. Reg. XII, X, 423.

^{page 22 note 3} Med. VI, VII, 83.

^{page 22 note 4} Princ. I, 66–70. Med. VI, VII, 83.

^{page 23 note 1} Princ. I, 64.

^{page 23 note 2} Ibid., 54.

^{page 24 note 1} Princ. I, 22.

^{page 24 note 2} IIae, IVae Resp., VII, 138–9, 233–4.

^{page 24 note 3} Princ. I, 34.

^{page 24 note 4} Thus Descartes writes that “the ideas which I have of heat and cold are so little clear and distinct that I cannot learn from them whether cold is only a privation of heat, or heat a privation of cold, or each is a real quality, or neither” (Med. III, VII, 44). It is hence in relation to such contemplated interpretation of their direct content, in which one wishes to “learn from them” the nature of the qualities they represent, that these ideas are lacking in clearness and distinctness. On the other hand, an interpretation of them in terms of biological utility finds the same ideas, i.e. the same direct contents, clear and distinct.

^{page 24 note 5} From this it can readily be seen that when the direct content is the basis of evaluation (as in Descartes's example of the clear but confused perception of pain in Princ. I, 46), ideas are usually clear, but their distinctness may come into question; on the other hand, when the interpretive content is made the basis, ideas may Often be lacking in clearness, but if they are clear, they will usually be distinct as well.

^{page 24 note 6} Cf. Reg. XIV, X, 439–40.

^{page 25 note 1} Iae, IIae, IIIae, Vae Resp., VII, 113, 147, 175, 368.

^{page 25 note 2} Princ. I, 53.

^{page 25 note 3} IVae Resp., VII, 225.

^{page 25 note 4} Ibid.

^{page 26 note 5} To Mersenne, 30 Sept. 1640; III, 191. Cf. IIae Resp., VII, 152. Conversation, V, 160.

^{page 25 note 6} Ibid., loc. cit.

^{page 25 note 7} IVae Obj., VII, 206.

^{page 25 note 8} Med. III, IV, VII, 37, 56–8.

^{page 25 note 9} Ibid., III, VII, 43.

^{page 26 note 1} Vae Resp., VII, 371.

^{page 26 note 2} IVae Obj., VII, 207.

^{page 26 note 3} IVae Resp., VII, 234.

^{page 26 note 4} To X***, Aug. 1641; III, 430.

^{page 26 note 5} For a statement of indifference as to whether ideas are expressed as terms or as propositions, cf. to Mersenne, July 1641; III, 395: “Car, qu'elles (les idées) s'expriment par des noms ou par des propositions, ce n'est pas cela qui fait qu'elles appartiennent à l'esprit ou à l'imagination; les unes et les autres se peuvent s'exprimer de ces deux manières. …” In another letter to Mersenne (22 July 1641; III, 417), Descartes writes: “Je n'entends pas bien la question que vous me faites, savoir si nos idées s'expriment par un simple terme; car les paroles étant de l'invention des hommes, on peut toujours se servir d'une ou de plusieurs, pour expliquer une même chose.…”

^{page 27 note 1} Reg. V, VI, XI, XII, X, 379, 383, 409, 410, 428.

^{page 27 note 2} Princ. I, 11. Cf. Med. II, VII, 33.

^{page 27 note 3} Ibid., 63.

^{page 27 note 4} IVae Resp., VII, 220. Cf. IIae Resp., VII, 140, 152.

^{page 27 note 5} Vae Resp., VII, 368.

^{page 28 note 1} Med. V, VII, 64. Cf. Reg. XII, X, 422. Conversation, V, 151–2.

^{page 28 note 2} Vae Resp., VII, 371. Cf. ibid., 368.

^{page 29 note 1} Cf. IIae Resp., Def. II, VII, 161, and especially IVae Resp., VII, 222, where Descartes shows that substance is that which is interpreted to be the subject of directly perceived ideas.

^{page 29 note 2} Cf. Princ. I, 47.

^{page 30 note 1} IIae Resp., VII, 147.

^{page 30 note 2} Ibid., 152.

^{page 30 note 3} Reg. V, X, 379. The de omnibus dubitandum of the First Meditation is just such a systematic reduction of ideas received “from the senses or through the senses,” to the thoughts which are their elements.

^{page 30 note 4} Reg. XII, X, 418–420, 422. The further refinements which Descartes makes on this doctrine of the simple or primitive “notions” (Princ. I, 47 ff., and to Elizabeth, 21 May 1643; III, 663), since they involve essentially the same principle as the discussion of the Regulae, although in a broader context, are here passed over.

^{page 31 note 1} Iae, IIae, Resp., VII, 113, 147–8.

^{page 31 note 2} Cf. IIae, IVae Resp., VII, 140, 152, 221.

^{page 31 note 3} Reg. XIV, X, 440.

^{page 31 note 4} Iae Resp., VII, 116.

^{page 31 note 5} To Gibieuf, 19 Jan. 1642; III, 474. Cf. VIae Resp. VII, 443.

^{page 31 note 6} Iae Resp., VII, 117.

^{page 32 note 1} Reg. XII, X, 429.

^{page 32 note 2} “Remanet adhuc eadem cera? Remanere fatendum est; nemo negat, nemo aliter putat. Quid erat igitur in ea quod distincte comprehendebatur? Certe nihil eorum quae sensibus attingebam; nam… mutata jam sunt: remanet cera.” Med. II, VII, 30. Cf. Princ. II, 4.

^{page 33 note 1} Med. II, VII.

^{page 33 note 2} Med. V, VII, 67, 11. 21–4. It is because Descartes holds that he has shown in this way that the idea of God as ah infinitely perfect being represents a true or real essence, and is not merely a nominal definition, that he maintains that his ontological argument, unlike that of St. Anselm as reported by Thomas Aquinas, is neither verbal nor fallacious. Cf. Iae Resp., VII, 115–19. To Mersenne, 15 June 1641; III, 383.

^{page 33 note 3} Definitions by genus and differentia, as viewed in the Aristotelian tradition, presuppose essentially different kinds of things, so that to define any given species requires showing the genus to which the species belongs, and then the form which differentiates it from other species of the genus and constitutes it what it is. Such definitions are hence basically additive: the differentia adds a characteristic which is essentially other than that of any other species. The Cartesian definition by simple natures, on the other hand, adds no “new” characteristic, but consists in a different arrangement or “mixture” of the same basic elements possessed by all other things; such definitions are hence “mechanistic” (cf. the example of a right triangle to exhibit what is meant by “species,” Princ. I, 59). The only point at which the Aristotelian differentia would enter into the Cartesian scheme is in the initial separation of the “material” from the “intellectual” natures. There is, however, a certain analogy between the two methods; just as for Aristotle if the definition of a species states the genus alone it has not differentiated the species in question from other species, i.e. the definition is not “distinct,” but if it states the differentia it also includes the genus (cf. Met. VII 12, 1037b, 29 ff.); so for Descartes if a definitely idea contains that mixture of simple natures which represents the “formal nature” of its object, but other ingredients not necessarily connected therewith, the idea is clear but not distinct, but if it is distinct it is also clear (cf. Princ. I, 46).

^{page 34 note 1} Ilae Resp., VII, 138. Cf. Med. V, VII, 67–8. Conversation, V, 161.

^{page 34 note 2} Cf. Reg. XIV, X, 439.

^{page 34 note 3} To Mersenne, 16 Oct. 1639; II, 597.

^{page 35 note 1} Description du Corps Humain, XVIII, XI, 242.

^{page 35 note 2} Disc. VI, VI, 65.

^{page 36 note 1} Cf. IIae Resp., VII, 135.

^{page 36 note 2} Vae Resp., VII, 354.

^{page 36 note 3} Reg. III, X, 368.

^{page 36 note 4} Conversation, V, 160. Cf. Princ. I, 47 ff.