Descartes’ conception of health and decay

To set the stage, I will give an outline of Descartes’ theoretical views on health, which, as it will emerge during this discussion, are pretty consistent (and consistently ambiguous) throughout his work. It is well-known that Descartes ranked the development of medi-cine very high among the goals of science. In the “Preface to the French edition” of the

1 This paper was prepared with the support of OTKA projects K 120375 and 125012.

2 I quote a familiar formulation, by Shapiro: “The line Elisabeth presses shows Descartes that […] he need not deny that the way we find ourselves in the world will very much affect our thought… In the Passions, more than any other of his [works], Descartes respects the fact that we are embodied”. Shapiro 1999, 516. Gaukroger claims that “the correspondence brings to light a very significant change of focus in Des-cartes’s thought”. Addressing the theme of the passions called for “the appropriate notion of a substantial union needed to account for the source and nature of affective states”. Gaukroger 1995, 398–399.

Principles, we read that medicine is one of the branches that yield the “principal benefit of philosophy” (AT IX B 14–15 / CSM 1.186). In the Discourse on the Method, we are told that Descartes intended to devote his life to its pursuit (AT VI 63 / CSM 1.143 and AT VI 78 / CSM 1.151), which he confirmed in a letter dated much later.³ Not only did Descartes think it important to advance medicine; he had an almost boundlessly ambitious vision for it: “we might free ourselves from innumerable diseases, both of the body and of the mind, and perhaps even from the infirmity of old age, if we had sufficient knowledge of their causes and of all the remedies that nature has provided” (AT VI 62 / CSM 1.143. Cf. AT XI 223–224 / CSM 1.314).

Descartes’ medicine, insofar as it is concerned with bodily diseases with physical causes, is bound to be mechanistic; no doubt, this is the default case. In the Discourse, Descartes talks about deriving rules of medicine from the knowledge of nature (AT VI 78 / CSM 1.151). Since he understands the human body as a machine, it is natural to interpret his conception of health and sickness accordingly, and perhaps even to consider this as extend-ing to mental processes as well.⁴

The human body-machine idea remained with Descartes into his later years. He offers analogies on several occasions between the human body and a machine, and even identifies the human body as a machine:

I suppose the body to be nothing but a statue or machine […] We see clocks, arti-ficial fountains, mills, and other such machines which, although only man-made, have the power to move of their own accord in many different ways. But I am sup-posing this machine [the body] to be made by the hands of God, and so I think you may reasonably think it capable of a greater variety of movements than I could possibly imagine in it, and of exhibiting more artistry than I could possibly ascribe to it (AT XI 120 / CSM 1.99).

[…] those who know how many kinds of automatons, or moving machines, the skill of man can construct with the use of very few parts […] will regard this body as a machine which, having been made by the hands of God, is incomparably bet-ter ordered than any machine that can be devised by man […] (AT VI 55–56 / CSM 1.139).

And let us recognize that the difference between the body of a living man and that of a dead man is just like the difference between, on the one hand, a watch or other automaton (that is, a self-moving machine) when it is wound up and contains in itself the corporeal principle of the movements for which it is designed, together with everything else required for its operation; and, on the other hand, the same watch or machine when it is broken and the principle of its movement ceases to be active (AT XI 330–331 / CSM 1.329–330).

3 “The preservation of health has always been the principal end of my studies […].” Letter To [The Mar-quess of Newcastle], AT IV 329 / CSMK 275.

4 It has been claimed that Descartes simply extended mechanism to the mental in his “medical physiol-ogy”, see Carter 1983, 19.

The primary basis of this analogy or identification is the body’s self-moving nature. It is not the soul that produces movement in the body, as Aristotelians had thought; that is, although certain movements of the body do depend on the soul, the latter is not the general principle of the movement of the body. That principle is internal to the body: “the heat in the heart is like the great spring or principle responsible for all the movements occurring in the machine” (AT XI 227 / CSM 1.316). Accordingly, the reason why a dead body does not move is not that the soul has departed from it, but that “the heat ceases and the organs which bring about bodily movement decay” (AT XI 330 / CSM 1.329).

However self-contained the operation of the body appears to be in Descartes’ view, he also often emphasizes the intrinsic connectedness of mind and body. Apart from the sailor-and-the-ship disanalogy (which can be said to be about the way in which we perceive the unity of mind and body rather than the way they are actually united), Descartes talks about the incompleteness of mind and body when viewed from the perspective of their union:

It is also possible to call a substance incomplete in the sense that, although it has nothing incomplete about it qua substance, it is incomplete in so far as it is referred to some other substance in conjunction with which it forms something which is a unity in its own right.

Thus a hand is an incomplete substance when it is referred to the whole body of which it is a part; but it is a complete substance when it is considered on its own.

And in just the same way the mind and the body are incomplete substances when they are referred to a human being which together they make up (AT VII 222 / CSM 2.157).

If we are to understand the appropriate approach to physiological processes as mechanistic, what could Descartes say about pathologies where the mind, apparently related to the body in an intrinsic manner, is also involved? The extension of mechanism to the mental is of course not a real possibility in Descartes. Although the body does have determinate effects on the mind, in the etiology and treatment of psychosomatic diseases and mental prob-lems, the mind, with its own characteristics, is also involved; but there is a further problem as well, formulated by Lisa Shapiro in the following way:

On Descartes’ official position, living bodies are simply machines whose work-ings can be explained by appeal to the laws of physics. However, these laws do not in and of themselves allow us to distinguish when a machine is working well or badly. […] There seems to be nothing in the nature of either a clock or an animal-machine, taken on its own, which can tell us whether the machine is in good working order, or an animal is healthy. […] And so, there seems to be no good way to ground ascriptions of health to a human body by appeal to the body alone (Shapiro 2003, 422–423).

What does it mean to be sick? It is, Descartes writes in the Meditations, to have a nature that is “disordered”. However, the sick body also operates according to the laws of nature, just like the healthy one, so “disordered” functioning cannot be “unnatural” functioning.

When we say, then, with respect to the body suffering from dropsy, that it has a disordered nature because it has a dry throat and yet does not need drink, the term ‘nature’ is here used merely as an extraneous label. However, with respect to the composite, that is, the mind united to this body, what is involved is not a mere label, but a true error of nature, namely that it is thirsty at a time when drink is going to cause it harm (AT VII 85 / CSM 2.59).

This is the sense of nature “which is really to be found in the things themselves; in this sense, therefore, the term contains something of the truth” (ibid). Descartes does seem to be saying in this passage that no real norm of the adequate functioning of the body can be found by taking the body separately from the mind, and that the good and the harm of the composite of mind and body is the standard by which adequate functioning is to be measured.

Thus, although we may intelligibly talk about “bodily” and “mental” health in a Car-tesian context, health or illness belongs to the composite in the first place. By this I do not deny that for Descartes it is the body rather than the mind, that health (the survival of the composite) mostly depends upon. The reason for death is the decay of a fundamental part of the body, Descartes tells us in The Passions of the Soul, not the absence of the soul (AT XI 330 / CSM 1.329). But the break-down concerns the whole composite, even if is caused by bodily processes only.⁵