1 In preparation for publication between 1629 and 1633 as the second part of a broader work to be call Le Monde, the work was suppressed during Descartes’ lifetime. The two parts were published separately in 1664 by Clerselier as Le monde de M. Descartes, ou le Traitté de la lumière and L’Homme de René Descartes.

2 Written in the period 1629-1633, before Man, the Dioptrics was first published in 1637 along with the Discourse on Method.

3 The apt characterization belongs to E. J. Dijksterhuis, The Mechanization of the World Picture, trans. C. Dikshoorn (Oxford: Clarendon Press 1961).

4 Gilson’s discussion of Descartes’ criticisms of the Medieval doctrine of substantial forms shows the deep scientific significance Descartes attached to distinguishing concepts of matter and soul. For Descartes’ view that Scholastic-Aristotelean science profoundly confuses matter and soul, see Étienne Gilson, Études sur le rôle de la pensée médiévale dans le formation du système cartésienne (Paris: J. Vrin 1967) 141-84. See also Daniel Garber, ‘Semel in Vita: The Scientific Background to Descartes’ Meditations,’ in Amélie Rorty, ed., Essays on Descartes’ Meditations (Berkeley: University of California Press 1986) 83-91.

5 C. Adam & P. Tannery, eds., œuvres de Descartes, 11 vols. (Paris: L. Cerf 1897 to 1910), IV (hereafter cited as AT followed by volume and page); E.S. Haldane & G.R.T. Ross, trans., The Philosophical Works of Descartes, 2 vols. (New York: Dover 1955), I (hereafter cited as HR followed by volume and page).

6 The Dioptrics (4th Discourse), AT VI, 109; Descartes’ Discourse on Method, Optics, Geometry, and Meteorology, trans. Paul Olscamp (New York: Bobbs-Merrill 1965) 87 (hereafter cited as Olscamp).

7 For elaboration see my ‘A Word about Descartes’ Mechanistic Conception of Life,’ Journal of the History of Biology 8 (1975) 1-13.

8 AT XI, 119-41, 201·2; Descartes’ Treatise of Man, trans. (with extensive annotation and facsimili of the original French text) Thomas Steele Hall (Cambridge, MA: Harvard University Press 1972) 1-33; 112-13. (Hereafter, Hall’s translation will be cited as Hall.)

9 I am indebted to Georges Canguilhem, La formation du concept de réflexe aux XVIIe et XVIIIe siècles (Paris: Presses Universitaires de France 1955) 55, for urging the point; see also Canguilhem's ‘Organisme et modèles mechaniques: Réflexions sur la biologie cartésienne,’ Revue philosophique 145 (1955) 292-8, for a variation on the theme, and Martial Gueroult, Descartes selon l’ordre des raisons, vol. 2 (Paris: Aubier 1953), and Etudes sur Descartes, Spinoza, Malebranche et Leibniz (New York: Georg Olms 1970) Ch. 3. These matters are discussed by Geneviève Rodis-Lewis, ‘Limitations of the Mechanical Model in the Cartesian Conception of the Organism,’ in Michael Hooker, ed., Descartes: Critical and Interpretive Essays (Baltimore: The Johns Hopkins University Press 1978) 152-70.

10 Descartes’ Conversation with Burman, John Cottingham, trans. (Oxford: Oarendon Press 1976) 19. I owe this point (and the reference) to the illuminating discussion in Norman Kemp Smith, New Studies in the Philosophy of Descartes (London: Macmillan 1953) 166-88.

11 This is the point at which intelligent design on the part of human or God may need to be cited, but only as efficient cause, never as final cause. On this point see Descartes’ curt reply to Gassendi (Reply to the Fifth Set of Objections) that it is appropriate to admire God as the efficient cause of plants and animals (AT VII 374; HR II 223).

12 Description of the Human Body (which he did not complete). The relevant part is in AT XI 252-7; The Philosophical Writings of Descartes, J. Cottingham, R. Stoothoff, and D. Murdoch, trans., 2 vols. (Cambridge: Cambridge University Press 1985) I 321-4. (Hereafter, this translation will be cited as CSM.)

13 My thinking in this section and the next is influenced by A. C. Crombie, ‘Early Concepts of the Senses and the Mind,’ Scientific American, March, 1964 and ‘The Mechanistic Hypothesis and the Scientific Study of Vision,’ in S. Bradbury & G. L’E. Turner, eds., Historical Aspects of Microscopy (Cambridge: W. Heffer 1967).

14 I owe this point to John Yolton, Perceptual Acquaintance from Descartes to Reid (Minneapolis: University of Minnesota Press 1984).

15 I owe this point to A. C. Crombie, The Mechanistic Hypothesis.’ See Dioptrics, 6th Discourse; AT VI 130; Olscamp 101.

16 David Lindberg, Theories of Vision from al-Kindi to Kepler (Chicago: University of Chicago Press 1976); Gary Hatfield & William Epstein, The Sensory Core and the Medieval Foundations of Early Modem Perceptual Theory’ ISIS 70 (1979) 363-84; A. I. Sabra, ‘Sensation and Inference in Alhazen’s Theory of Visual Perception,’ in P. Machamer & R. Turnbull, eds., Perception: Philosophical and Scientific Themes and Variations (Columbus, OH: Ohio State University Press 1978).

17 I owe this point to Crombie, ‘The Mechanistic Hypothesis’ 67.

18 The introduction and notes in Hall's edition of the Treatise of Man provide a valuable guide through Cartesian neuromechanics. See especially xxxvii ff. and notes 62 and 124-6.

19 It is unclear whether the exit points on the gland itself or the pattern in the current of animal spirits constitutes this idea.

20 The theoretical sections of the Dioptrics propose that sense be treated as analogous to other cases which involve various kinds of representation, but the analogy is not defended or developed in detail; Man simply ascribes aspects of sense to the rational soul, displaying, but not defending, the view that those aspects elude mechanical treatment; the arguments in Part V of the Discourse on Method offered in support of the claim that all and only humans are distinguishable from machines do not relate in any obvious way to sense. It is worth noting also that although the entire passage concerning the ‘two very certain tests’ for the presence of mind in the Discourse on Method, Part V (AT Vl56-60; HRI 116-18) is presented as if in summary of material in Man, no counterpart in Man exists. So we have no documentary evidence of Descartes’ thought about the rational soul at the time he wrote Man.

21 This passage is quoted by Crombie in support of the claim that Descartes distinguishes objects of sense from means of sensing.

22 I am encouraged in this suggestion by John Yolton’s more sweeping interpretation of Descartes as holding that all sensory awareness is unmediated in this sense. See John Yolton, ‘On Being Present to the Mind: A Sketch for the History of an Idea,’ Dialogue 14 (1975) 373-88 and Yolton's Perceptual Acquaintance from Descartes to Reid, Ch. 1-3.

23 Principles of Philosophy, I article 71; AT VIIIA, 35; HR I, 249-50. The complete English translation of the Principles is by V.R. Miller and R.P. Miller (Boston: D. Reidel 1983), hereafter cited as MM. The passage appears in MM on p. 32.

24 Passions I, art. 13, AT XI, 338; HR I, 338 and art. 50, AT XI, 369; HR I, 355

25 I learned this (and much else) from Thomas Lennon, ‘Representationalism, Judgement and Perception of Distance,’ Dialogue 19 (1980) 151-62.

26 The most systematic recent study of this principle appears in Kenneth Clatterbaugh's ‘Descartes’ Causal Likeness Principle,’ Philosophical Review 89 (1980) 379-402. I owe the name of the principle to Clatterbaugh, and my discussion draws on his study. For a different perspective, which seeks Medieval origins of Descartes’ thought, see Calvin Normore's ‘Meaning and Objective Being: Descartes and His Sources’ in Amélie Rorty, ed., Essays in Descartes’ Meditations (Berkeley: University of California Press 1986) 223-41.

27 It appears in the context of a broader discussion of representation: AT VII 37-47; HR I 159-65. See also Descartes’ Replies to the First and Fourth Sets of Objections: AT VII 102-6; HR II 9-12 and AT VII 232-5; HR II 105-7.

28 My definition of formal inherence follows Clatterbaugh’s (386); my definition of objective inherence modifies Clatterbaugh's (387).

29 I attach a good deal of importance to this principle because I think it shows that Descartes adopts a treatment of representation (in general) which is fundamentally extensional. But demonstrating this requires separate study.

30 This implies that we cannot sense other people’s thoughts; but of course Descartes agrees with this implication.

31 I will consider (below) the suggestion that Descartes also, on occasion, seems to equate colours etc. with the mechanical bases in physical objects of sensations.

32 I owe this important point to Wilfrid Sellars, ‘Berkeley and Descartes: Reflections on the Theory of Ideas’ in Peter Machamer & Robert Turnbull, eds., Studies in Perception (Columbus: Ohio State University Press 1978) 265.

33 Obviously, this does not constitute anything like a satisfactory answer to Rorty's question, ‘What do pains and intentional states have in common?’ but at least there is a covering label, available to Descartes, which makes it appear that they are both instances of some single kind. See Richard Rorty, Philosophy and the Mirror of Nature (Princeton, NJ: Princeton University Press 1979), Chapter 1.

34 This is developed in Descartes’ celebrated account of the rainbow in the Meteors, Discourse 8, but the general idea is cited both in the Dioptrics and in Man.

35 I am indebted to unpublished work by John Nicholas for calling these passages to my attention.

36 See, for example, Dennis Stampe, ‘Toward a Causal Theory of linguistic Representation’ in P. French, T. Uehling, and H. Wettstein, eds., Contemporary Perspectives in the Philosophy of Language (Minneapolis: University of Minnesota Press 1979) 81-102; Robert Stalnaker, Inquiry (Cambridge, MA: MIT Press 1984), Ch. 1; John Haugeland, Artificial Intelligence: The Very Idea (Cambridge, MA: MIT Press 1985), Ch. 1 and 3.

37 Descartes provides a sketch of the analytic geometry in his Rules for the Direction of the Mind (a project which he abandoned in 1628 before completion), and a more developed version in his Geometry, published in 1637. For a fascinating study of the Rules, which emphasizes Descartes’ early scientific concerns, see John A. Schuster, ‘Descartes’ Mathesis Universalis, 1619-1628’ in Stephen Gaukroger, ed., Descartes: Philosophy, Mathematics and Physics (New York: Barnes & Noble 1980) 41-96.

38 ‘The World, Chapter 1. AT XI 4; CSM I 81. The French is’ … des mots, que ne signifient rien que par l'institution des hommes ….’

39 D.C. Dennett, ‘A Cure for the Common Code?’ in Dennett's Brainstorms (Montgomery, VT: Bradford Books 1978) 101

40 It is curious that Descartes does not recognize (explicitly at least) that knowledge of New Science will give the mind the capacity to exploit information carried by sensations. Since, according to Descartes, sensations are causally hooked up in the right way to mechanical bases in physical objects, there should be nothing stopping the mind from treating sensations as vehicles of representation, the objects of which are the mechanical bases. To be sure, the mechanical basis of colour, i.e. the corpuscular spin caused by reflected or refracted light, for example, is invisible at the level of sensory representation. But at a higher level of representation, the mind should be able to use its knowledge of physics to read this spin off the sensation of colour.