The Will between Mind and Body
This last account, nevertheless, seems to entail a serious risk, namely, a full dissolution of the soul’s action within a certain behavioural economy. From a Cartesian point of view, can we conceive that the voluntary would be reduced to the usual, and that what the soul itself tends to do, what it tries to make prevail in such or such circumstance, is entirely predetermined in the constitution of the composed being?
We can here cite an amazing text, the crucial significance of which Clarke alone seems to have acknowledged: the preface to the unfinished treatise of 1648, The Description of Human Body. This text deals at first with involuntary movements insofar as they give evidence of the limits of the soul’s power:
We can observe... that when some parts of the body are harmed, for example when a nerve is irritated, the result is that the parts in question cease to obey our will as they normally do, and sometimes are subject to convulsive movements despite our wishes. This shows that the soul cannot produce any movement in the body without the appropriate disposition of the bodily organs that are required for making the movement. On the contrary, when all the bodily organs are appropriately disposed for some movement, the body has no need of the soul in order to produce that movement.
This point conforms to several other Cartesian claims, as well as what immediately follows: ‘and, as a result, all the movements which we in no way experience as depending on our thought must be attributed not to the soul, but simply to the disposition of the organs’.28 The last statement of this section is much more surprising:
Even the movements which we call ‘voluntary’ occur principally as a result [dependent principalement] of this disposition of the organs, since, although it is the soul that determines these movements, they cannot be produced without the requisite disposition of the organs, no matter how much we may will this to happen.29
What is amazing here is a sort of reversal in the causal priority. The movements which we call voluntary, Descartes says, cannot be excited without a certain disposition of the organs: but this ‘cannot without’ is not enough for making this disposition appear as the principal cause of these movements. Here is the step Descartes takes: these movements, he says, ‘occur principally as a result of this disposition’, and the soul (which we would consider, with its will, as their principal or at least their highest cause) just ‘determines’ them. The necessary condition of these movements seems to have become their sufficient one.
Why does Descartes go so far as to set out things in such a way? The answer is not obvious, but there is no evidence that what applies to voluntary movements which are straightforward and comparatively simple (for example, to put one’s arm up) would not equally apply to any action that the soul would wish to product in the body (including extinguishing a definite passion).
What does it mean then to say that the soul ‘determines’ those movements? One can conceive only two responses to this question:
- (1) The soul has to choose between two physiological possibilities, and maybe between two different tendencies that are predetermined in the body; in that case, it exerts an action in the body, which can be as slight as one will like, for we know that from a Cartesian point of view, a very small action occurring in a mechanical system, for instance in the distribution of the animal spirits in the brain, may be of very important physical consequence.
- (2) The only operation of the soul consists in electing (either for itself, or for the compound it forms with the body), in a simple thought of assent or authentication, what constitutes at a given moment the prevalent tendency of the body (including of course the brain) or the object of this tendency.
The first assumption has been favoured by Frederic de Buzon in the study we have jointly authored. It is consonant with some other significant Cartesian accounts— especially with the hydraulic system activated by an engineer to which the Treatise on Man alludes. Its advantage consists in reducing the physical reality of the soul’s ‘force’ to an infinitesimal quantum; its disadvantage consists in requiring for the soul’s action this physical quantum, and the doubt remains, moreover, whether the physiological conditions of this action can be specified.
The second assumption corresponds to Desmond Clarke’s account, according to which the will may be understood as ‘supervenient’ to the body. Its advantage is that the physical problem vanishes. It vanishes, nevertheless, insofar as the soul is now deprived of any real action on the body, the term ‘to determine’ having to be taken in an especially weak acceptation, even weaker than the one which can be found in Malebranche’s or Leibniz’s writings. This account may therefore be questioned in several ways:
(1) Where historical connections are concerned, are we not discovering here in Descartes a psycho-physical parallelism of the Spinozan kind? What will remain of the well-known opposition between Descartes and Spinoza concerning the mind-body connection?
- (2) If we conclude that the soul never acts except in a predisposed brain, aren’t we abolishing or at least reducing its freedom, again in a quite Spinozan way?
- (3) Can we claim that the problem of the soul’s struggle against its present passion is really solved, if we have to conceive here a given disposition of the organs impeding another one?
-  Clarke, Descartes’s Theory of Mind, 137. 2 AT xi, 225; CSMK1, 315.
-  28 Ibid. 29 Ibid.
-  Frederic de Buzon and Denis Kambouchner, L’ame avec le corps: les sens, le mouvement volontaire, lespassions, in F. de Buzon, E. Cassan, D. Kambouchner, eds, Lectures de Descartes (Paris, 2015), 279-328.
-  Cf. AT xi, 131.
-  Clarke, Descartes’s Theory of Mind, 157.
-  When Malebranche says that the soul can diversely ‘determine’ the movement or impression towardthe Good in general, which it has received from God and which defines the will itself, this determinationwill imply a sort of reorientation or deviation with respect to an initial tendency (The Search after Truth, I,I, ii). And in Leibniz’s comments on the Cartesian account of the union of mind and body, the movement ofthe gland ‘determines’ that of the animal spirits in the brain insofar as the gland which was leaning to oneside is now leaning to another side (see especially Leibniz to Arnauld, 30 April 1687; and the Essays ofTheodicy, } 60).