2 ‘AT’ = Adam, C. and Tannery, P. eds., Oeuvres de Descartes (Paris: J. Vrin 1904)Google Scholar; ‘CSM’ = Cottingham, J. Stoothoff, R. and Murdoch, D. eds., The Philosophical Writings of Descartes (Cambridge: Cambridge University Press 1984)Google Scholar; ‘CSMK’ =Volume III of CSM for which Anthony Kenny is a contributing translator. References to both AT and CSM are to the volume and page.

3 Cf. Bennett, J. ‘Thoughtful Brutes,’ Presidential Address, American Philosophical Association (1988), 199Google Scholar; Chomsky, N. Cartesian Linguistics (New York: Harper and Row 1966), 78n.9Google Scholar; Cottingham, J. ‘Cartesian Dualism: Theology, Metaphysics, and Science,’ in Cottingham, J. ed., Cambridge Companion to Descartes (Cambridge: Cambridge University Press 1992), 250CrossRefGoogle Scholar; Radner, D. and Radner, M. Animal Consciousness (Buffalo: Prometheus Books 1989), 41Google Scholar; Rozemond, M. ‘The Role of the Intellect in Descartes's Case for the Incorporeality of the Mind,’ in Voss, Stephen ed., Essays on the Philosophy and Science of Rene Descartes (Oxford: Oxford University Press 1993), 99Google Scholar; and Wilson, M.D. ‘Animal Ideas,’ Presidential Address, American Philosophical Association (1995), 12.Google Scholar

4 Cf. Cottingham, ‘Cartesian Dualism,’ 250)Google Scholar.

5 Cf. Loeb, L.E. From Descartes to Hume (Ithaca: Cornell University Press 1981), 112fGoogle Scholar; Radner, D. and Radner, M. Animal Consciousness, 79Google Scholar; and Vendler, Z. Res Cogitans (Ithaca: Cornell University Press 1972), 152ffGoogle Scholar.

6 Cf. Cottingham, J. ‘A Brute to the Brutes? Descartes's Treatment of Animals,’ in Cottingham, J. ed., Descartes (Oxford: Oxford University Press 1998), 230Google Scholar; and Gaukroger, S. Descartes (Oxford: Clarendon 1995), 289Google Scholar.

7 The general disfavor into which these doctrines have fallen render this an enormously generous assumption. Bear in mind that my aim is to clarify why Descartes would think — in the light of his philosophical system — that the bête machine doctrine provides the best account of observed behavior in brute animals.

8 In Discourse 4, Descartes contrasts metaphysical certainty with moral certainty. Morally certain matters are such ‘that it seems we cannot doubt them without being extravagant’ (CSM 1:130, AT 6:37-8; d. Principles 4:205-6).

9 Descartes adds: ‘Our ignorance of anatomy and mechanics has also played a major role here. For in restricting our consideration to the outside of the human body, we have never imagined that it has within it enough organs or mechanisms to move of its own accord in all the different ways which we observe’ (ibid.).

10 Montaigne, M. The Complete Essays of Montaigne, Frame, D. trans. (Stanford, CA: Stanford University Press 1957), 336Google Scholar

11 As is that of other nouveaux Pyrrhoniens — cf. the defense of Pierre Charron (a disciple of Montaigne), in his Of Wisdom.

12 To More, Descartes writes: ‘There are two different principles causing our movements. The first is purely mechanical and corporeal, and depends solely on the force of the spirits and the structure of our organs …. The other, an incorporeal principle, is the mind or that soul which I have defined as a thinking substance’ (CSMK 365, AT5:276).

13 In the Fourth Replies, Descartes writes: ‘both in our bodies and those of the brutes, no movements can occur without the presence of the all the organs or instruments which would enable the same movements to be produced in a machine. So even in our own case the mind does not directly move the external limbs, but simply controls the animal spirits which flow from the heart via the brain into the muscles, and set up certain motions in them; for the spirits are by their nature adapted with equal facility to a great variety of actions’ (CSM 2:161, AT 7:229).

14 Cf. the World, AT 11:7 and 11:25-6, for more on how Descartes understands scholastic hylomorphic explanation.

15 Cf. the Treatise on Man, AT 11:202, and Passions 16 (AT 11:341f). Though such behavior is typically automatistic, it sometimes issues from the soul; Descartes cites willful changes in respiration (AT 11:197) and pupil adjustment (AT 11:361f).

16 Cf. Aquinas, Thomas Summa Theologica (abbreviated ST) (New York: Blackfriars and McGraw-Hill 1964-), 1a.80.1, 1a.81.2-3.Google Scholar

17 In his Treatise on Man, Descartes shows special interest in explaining seemingly purposive external behavior. For instance, he writes that ‘the effect of [corporeal] memory here that seems to me the most worthy to be considered consists in this, that without there being any soul in this machine, it can naturally be disposed to imitate all the movements of real men, or other similar machines’ (AT 11:185). The account then unfolds (AT 11:185-197) with Descartes explaining how mechanical physiology alone can account for a variety of behavior appropriate to various stimuli, via a wholly reflex mechanism, including: complex eye adjustments, and the corresponding corporeal signals sent to the brain; behavior in which the movements of the limbs, the head, and the eyes, are coordinated (e.g. when the hand is burned, the reflexive response includes tears, a wrinkling of the face, and a disposition of the voice to cry (AT 11:192f)); behavior that ‘serves to pursue desirable things, or to avoid the harmful’ (AT 11:193); behavior that in real men serves only ‘to manifest the passions’ (à témoigner les passions) (AT 11:194), including laughing and crying; leg movements requisite to walking (AT 11:196f); and much more.

18 Cf. the Treatise on Man, AT 11:131f, and the thought-experiment in the letter of April or May 1638 (to Reneri for Pollot).

19 For Descartes, the mechanical workings in questionn—qua modes of body—would not even be ‘signs’ were they not so regarded by a mind. Cf. Searle, J.R. The Rediscovery of the Mind (Cambridge, MA: The MIT Press 1992)CrossRefGoogle Scholar, who makes a similar point about symbols and syntax (ch. 9).

20 In Principles 4:205, Descartes characterizes morally certain matters as ‘having sufficient certainty for application to ordinary life, even though they may be uncertain in relation to the absolute power of God’ (CSM 1:289-90, AT 8a:327).

21 Given standard mechanist doctrines that Descartes helped establish — whereby all possible variety of secondary quality ideas can be produced (in stimulus-response fashion) by none other than variations of corporeal motion — he surely did not underestimate the potential indefiniteness in the variety of output responses that can be mapped to sequences of just a few kinds of input stimuli (cf. Principles 2:23). Note, too, that given the implications of his non-atomist version of mechanism, it is unlikely that Descartes underestimates the potential for miniaturization in machines (cf. Principles 2:20, 2:34-5).

22 In contrast with my reading, Cottingham's reading of Discourse 5 commits Descartes to assumptions about the abilities of machines that, says Cottingham, we today know to be false (‘Cartesian Dualism,’ 250).

23 Though of course via his hylomorphic conception of the beings Descartes regards as pure machines.

24 For Descartes, all purely mechanical behavior displays the order and purpose of the divine will. In his Sixth Meditation discussion of dropsy error, Descartes notes that even where machines (whether clocks or physiological systems) appear to be malfunctioning, they behave in accordance with their God-given natures (AT 7:83ff).

25 The distinction between reasoned₁ and reasoned₂ behavior is similar to, but not exactly the distinction between acting on a reason and acting in accordance with a reason. As I mean to construe it, reasoned₂ behavior is not merely in accordance with reason — not merely reasonable. Rather, there is a sense in which such behavior occurs because of a reason— it is reasoned — though the guiding reasons are not the behaver's own.

26 In other cases, the disposition is acquired without any volitional contribution from the behaver. In a 1630 letter, Descartes describes what he regards as such a case: ‘I reckon that if you whipped a dog five or six times to the sound of a violin, it would begin to howl and run away as soon as it heard that music again’ (CSMK 20, AT 1:34).

27 An analogical argument focusing on behavior would seem to offer the most promising strategy available to Descartes. Granting his substance dualism (among our assumptions, for purposes of understanding his project), there's no possibility of identifying structures of the central nervous system in humans in which consciousness resides, so as to infer to the existence or non-existence of consciousness in brutes based on the presence or lack of similar such structures.

28 Discourse 5 is weak in this regard, though, in his post-Discourse writings, Descartes improves. For example, in the Fourth Replies he offers the following argument: ‘When people take a fall, and stick out their hands so as to protect their head, it is not reason that instructs them to do this; it is simply that the sight of the impending fall reaches the brain and sends the animal spirits into the nerves in the manner necessary to produce this movement even without any mental volition, just as it would be produced in a machine’ (CSM 2:161, AT 7:229-30). Elsewhere, Descartes strengthens the introspective force of the argument, adding that ‘even if we expressly willed not to put our hands in front of our head when we fall, we could not prevent ourselves’ (CSMK 302-03, AT 4:573; cf. also Passions 13).

29 The standard interpretation of Descartes has it that his two tests are intended to yield either a positive or a negative outcome— i.e., that they are intended to reveal whether or not a behavior is reasoned₁. Cf. Bennett, ‘Thoughtful Brutes,’ 199Google Scholar; Chomsky, Cartesian Linguistics, 78n.9; Cottingham, ‘Cartesian Dualism,’ 250Google Scholar; Radner and Radner, Animal Consciousness, 41; Rozemond, ‘The Role of the Intellect,’ 99Google Scholar; and Wilson, ‘Animal Ideas,’ 12Google Scholar, all of whom are committed to the claim that Descartes intends the tests as both positive and negative tests.

30 Descartes's early notebooks record related thoughts: ‘The high degree of perfection displayed in some of their actions makes us suspect that animals do not have free will’ (CSM 1:5, AT 10:219).

31 He adds, ‘spirits are by their nature adapted with equal facility to a great variety of actions’ (CSM 2:161, AT 7:229)

32 The example is cited by Dennett, D. ‘Mechanism and Responsibility,’ in Honderich, T. ed., Essays on Freedom and Action (London: Routledge & Kegan Hall 1973)Google Scholar, who uses it to illustrate a rather different point.

33 Wooldridge, D.E. The Machinery of the Brain (New York: McGraw-Hill 1963), 82–3Google Scholar

34 The parenthetical qualification is crucial, as it is unreasonable to expect behavior for which the organism is anatomically unfit. In some passages, Descartes shows a sensitivity to such concerns (cf. AT 6:57f, AT 4:575).

35 There is a weak and a strong reading as to the immediate conclusion we're to draw from an unmasking. On the weak reading, an unmasking shows that the behavior in question is not reasoned₁. On the strong reading, it shows that the behaver in question lacks a faculty of reason — because (as this reading would have it) any organism in possession of a faculty of reason would employ it in the scenarios at play in the unmasking. Though there are some textual grounds for the stronger reading, I believe that Descartes is best interpreted according to the weak reading.

36 The superiority of the behavior of brutes is among Montaigne's central themes: ‘we recognize easily enough, in most of their works, how much superiority the animals have over us and how feeble is our skill to imitate them’ (333).

37 The italicized remarks were added to the 1595 edition of Montaigne's Essays. The changes signal no more than a shift in emphasis, as they are entailed by the original version of the causal principle, namely, from like effects, like causes.

38 The passage poses translation difficulties because of the ambiguous reference in connection with the remark, ‘car, à ce compte, ils en auraient plus qu'aucun de nous.’ (They would have more of what than any of us?) Most translations take the remark to refer back to ‘esprit,’ thus resulting in the awkward claim that brutes would have more mind than any of us. (I can make no clear sense of the claim that ‘x has more mind than y.’) CSM avoids this, but only with the somewhat strained translation of esprit as ‘intelligence.’ I take the referent to be ‘industrie,’ resulting in a very natural translation (albeit too literal) in connection with my unmasking interpretation — brutes would have more ingenuity than any of us.

39 It's worth noting that Descartes intended to run further experiments but evidently never found time. In a 1645 letter (probably) to the Marquess of Newcastle, Descartes writes: ‘The treatise on animals, on which I began work more than fifteen years ago, cannot be finished until I have made many observations which are essential for its completion, and which I have not yet had the opportunity to make (nor do I know when I shall have it)’ (CSMK 274, AT 4:326). Essentially the same point is made to More (AT 5:344), in the penultimate year of Descartes's life.

40 Though this need not be arbitrary where such behavior (cf. oysters) is well below any plausible threshold range.

41 In Passions 21 and 25, Descartes explains that he uses ‘passion’ with dual reference. In discussions related to brutes and consciousness, he uses the term in (what he calls) the more general sense, roughly the sense whereby our passions are those occurrences that happen to us purely mechanically, rather than being made to happen by our thought (cf. Passions 1).

42 In effect, assume with Montaigne that the signing of ‘blackbirds, ravens, magpies, and parrots,’ and other brutes, ‘testifies that they have an inward power of reason’ (cf. 339-40). Montaigne extends his position to all manner of bodily signs, not just verbal ones (332). Descartes would have us extend our assumption to the same (cf. AT 6:58, 4:574).

43 Prima facie, this remark implies that Descartes does not mean to deny brutes such consciousness states as anger, fear, hunger, and the like. I shall return to this in §IV.1.

44 Bennett (202-6) offers an interesting overview of some recent experimental work (by David Premack, et al.) that purports to establish that brutes exhibit stimulus-free signing behavior. Among other things, the discussion highlights the difficulties involved in establishing signs as stimulus-free.

45 Descartes does not deny that mechanical systems may incorporate- what is, from the point of view of their designer—signaling. He indeed characterizes the motions of animal spirits in our nerves as signals (cf. AT 7:86ff), though of course purely corporeal signals.

46 In significant respects, the procedure is similar to Alan Turing's Imitation Game. See Turing, A. ‘Computing Machinery and Intelligence,’ Mind 59 (1950) 433–60CrossRefGoogle Scholar. But where Turing's test aims at unmasking the causes of an exhibition of behavior as involving thinking (i.e. insofar as the notion of thinking, on his view, is to be meaningful), Descartes's tests aim at unmasking the causes as purely mechanical. (I should add that there is no easy way to link Turing's concept of thinking with any concept in Descartes's scheme.)

47 One plausible explanation of the seemingly cursory treatment is that Descartes intends the discussion of non-linguistic behavior — a discussion I have been suggesting is to be understood as presenting an independent unmasking- to be a continuation of the earlier argument addressing linguistic behavior. Descartes might thus intend to treat the universal lack of language in brutes (as he thinks he's now shown) as primary evidence relevant to the non-linguistic urunaskings. So understood, the reasoning (again, analogical) might run as follows. As he's already argued, ‘it patently requires very little reason to be able to speak’ - a claim he supports by analogy to various humans with marginal intellects (CSM 1:140, AT 6:58). But, in accordance with the Universal Instrument Thesis, it is implausible that any organism that does not use language would excel us in any manner via the assistance of reason. The better explanation of such ‘superior’ behavior is that it is produced purely mechanically. Assuming this is the correct reading, Descartes's linguistic unmasking test is perhaps intended to apply to every brute animal that exhibits any behavior of type (C) -a not implausible thesis, given how pervasive are passionate signings among brutes.

48 Montaigne rhetorically asks, ‘Do the swallows that we see on the return of spring ferreting in all the comers of our houses search without judgment, and choose without discrimination, out of a thousand places, the one which is most suitable for them to dwell in?’ (333)

49 Montaigne asks, ‘Is there a society regulated with more order … than that of the honeybees? Can we imagine so orderly an arrangement of actions and occupations as this to be conducted without reason and foresight?’ (332)

50 Montaigne recounts the dog whose behavior results from an ‘act of pure logic’ involving the ‘use of propositions divided and conjoined’ (339). Of foxes, he suggests that they use ‘the same reasoning’ as humans (337).

51 Cf. Chomsky, 4ff.

52 Elsewhere, it is clear that Descartes thinks brutes can be taught in the sense of being conditioned (by means of rewards and punishments) via none other than purely mechanical processes. (See note 26.)

53 Again (cf. note 43), such remarks might seem to imply that Descartes allows brutes such conscious states as fear, hope, and joy. I shall return to this in §IV.1.

54 Alan Turing's famous example of a linguistic exhibition that passes his own (Turing) test (446) would not qualify as type (A) behavior in view of the stimulus-dependent character of the witness's responses to the interrogator.

55 Given my weak reading of the unmasking tests, whereby Descartes intends to unmask behavior not behavers (cf. note 35), the alleged non sequitur arises not only in connection with epiphenomenal sensation, but also epiphenomenal rationality. On a more standard interpretation, however, since Descartes's two tests are supposed to show that brutes lack a faculty of reason, the non sequitur arises only in connection with epiphenomenal sensation. I shall thus focus my attention on this latter understanding of the alleged non sequitur.

56 Cf. Radner and Radner (79), Loeb (112f), and Vendler (152ff).

57 Cf. Cottingham, ‘A Brute to the Brutes?’ 230Google Scholar; and Gaukroger, 289 and 454n.165.

58 In response to a critic of the Discourse who supposes that Descartes allows that brute ‘animals see just as we do, i.e. being aware,’ Descartes clarifies that, in his view, brutes ‘do not see as we do when we are aware that we see, but only as we do when our mind is elsewhere. In such a case the images of external objects are depicted on our retinas, and perhaps the impressions they make in the optic nerves cause our limbs to make various movements, although we are quite unaware of them. In such a case we too move just like automatons’ (CSMK 61-2, AT 1:413-14).

59 Cf. the 1637letter (of October 3) to Plempius for Fromondus (AT 1:414f).

60 The one exception is the human soul, which Descartes regards as the substantial form of a human (cf. Hoffman, P. ‘The Unity of Descartes’ Man,’ Philosophical Review 95 [1986] 339–70)CrossRefGoogle Scholar and which he does not attempt to eliminate.

61 Garber broaches the subject of parsimony, observing that the case against animal souls is analogous to the case against substantial forms. See Garber, D. Descartes’ Metaphysical Physics (Chicago: University of Chicago Press 1992)Google Scholar. My claim is much stronger. Garber indeed worries that ‘Descartes may not have explicitly made the connection’ between parsimony and the bête machine doctrine (115f). Rozemond, M. Descartes's Dualism (Cambridge, MA: Harvard University Press 1998)Google Scholar, ch. 4, offers a superb discussion of Descartes on parsimony, but she does not make the link to the bête machine doctrine.

62 Voetius (the Rector of the University of Utrecht) had tried to remove Regius from his Chair at the University.

63 Rosenfield, L.C. does, in her very useful From Beast-Man to Man-Machine (New York: Oxford 1940).Google Scholar