Flow of Ideas


Discuss Descartes’s account of the relation between mind and body

Alexander Rikowski

London, 12th January 2009

According to Descartes, a mind is a non-physical thinking substance with no extension, but bodies are substances which have extension and take up space (Gueroult, 1985, pg. 47).

“In modern philosophy, a substance is a thing capable of independent existence” .

I will demonstrate how Descartes argues for the distinction between mind and body and I will also show how for Descartes, a human being is a composite or union of a body and a mind. This essay will explain how Descartes argues we can know that a perfect, non-deceiving creator named as God exists, and that as long as we use the nature of our mind in the correct way, we can recognize that the mind and the body really are distinct substances. Elizabeth of Bohemia wrote to Descartes asking him how there can be causal relationships between non-physical minds and physical bodies when physical objects can only be affected by physical things. Although Descartes aimed to dissolve the problem raised by Elizabeth by explaining that a human being has a mind and body which are intermingled with one another, modern science still offers reasons to disbelieve in non-physical minds (Smith and Jones, 1986, pg. 59).

In the fifth meditation, Descartes gives an ontological argument for the existence of God (Grayling, 2005, pg. 89). The argument is that the idea of God is one of perfection, and that as existence is a perfection; God must necessarily exist (Grayling, 2005, pg. 89). Descartes understood existence as being the essence of God (Descartes, 1996, pg. 46). Grayling (2005, pg. 89) explains that the problem with this argument is that, as Kant demonstrated, existence is not a predicate. A predicate is a property which says something about a concept, but since ‘existence’ does not add anything new to a concept, it cannot then be a logical predicate (Grayling, 2005, pg. 89-90). As ‘existence’ cannot be a logical predicate, it cannot be used in an argument to prove that God necessarily exists, says Kant (Grayling, 2005, pg. 90). Nonetheless, Descartes himself believed that he had proven the existence of God in his Meditations, and after doing so, he went on to inquire into what else can be known once one knows that God exists.

Having believed he had proven the existence of a perfect creator (God), Descartes stated that as God is perfect, he cannot be a deceiver (Patterson, 2008, Handout 7, pg. 2). God’s existence reassures us that whatever we perceive clearly and distinctly must be true, says Descartes (Descartes, 1996, pg. 54).

“First, I know that everything which I clearly and distinctly understand is capable of being created by God so as to correspond exactly with my understanding of it” .

Descartes argued that he could clearly and distinctly understand his mind as being a substance that is distinct from his body (Patterson, 2008, handout 6, pg. 1). In the second meditations, Descartes supposes that everything he perceives is false and that he has no body or senses (Descartes, 1996, pg. 16). Doubting is a kind of thought, and after doubting he had a body, Descartes realised that as he must still exist as a thing that doubts and thinks (Descartes, 1996, pg. 18). As Descartes realised that he must exist even after supposing he had no body, he concluded that he is essentially a non-physical mind which thinks and is distinct from his body (Descartes, 1996, pg. 54). All this leads him to conclude in the sixth meditation that: “And accordingly, it is certain that I am really distinct from my body, and can exist without it” . However, Patterson (2008, handout 6, pg. 2) makes the point that just because the mind can be conceived of as being distinct from the body, this does not mean that the mind really can exist without the body.

God being perfect means that he would not continuously deceive us about material objects existing and being extended in space (Patterson, 2008, Handout 7, pg. 2). Descartes explains that God made him in such a way that as long as he uses his own nature properly, he will not be completely mistaken (Descartes, 1996, pg. 56).

“There is nothing that my own nature teaches me more vividly than that I have a body, and that when I feel pain there is something wrong with the body”.

Descartes then goes on to explain that he as a non-physical thinking mind, cannot be within his body in the same way as a sailor is in a ship, because he does not perceive pain in his body as though it is not him who is actually feeling that pain. Rather, Descartes concludes that as he can feel his body and has sensory perception which allows him to imagine certain physical objects taking up space, his mind and his body must be “intermingled” with one another (Descartes, 1996, pg. 56). Descartes states that sensations such as hunger and thirst are: “nothing but confused modes of thinking which arise from the union and, as it were, intermingling of the mind and the body” . Elizabeth of Bohemia however, makes the reasonable point to Descartes that she cannot see how a non-physical mind can cause a body to move, since only physical things can move other physical things (Skirry, 2005, pg. 145).

Descartes aimed to get Elizabeth to realise that she was misunderstanding the relationships between the mind and the body (Skirry, 2005, pg. 164). As Skirry says: “Descartes’s remarks to Elizabeth indicate that mind and body do not efficiently or mechanistically causally interact as she and Gassendi supposed” . Descartes uses an analogy of the then common conception of gravity to show how mind and body interact (Mattern, 1978, pg. 215). In this analogy, he explains that the gravity of a body causes it to move to the centre of the earth, without that body being touched by something physical. Whilst the gravity of the body is distinct from the body, it is also “conjoined” to it, says Descartes (Mattern, 1978, pg. 215). Descartes is making the point to Elizabeth that she and many others do in fact have a conception of something non-physical causing something physical to move, and Descartes uses their conception of gravity as an analogy of how the mind causes the body to move by being intermingled with it (Mattern, 1978, pg. 215). However, as Skirry (2005, pg. 167) explains, there is still the problem of demonstrating how exactly an immaterial mind can be conjoined with a physical body.

God’s existence was supposed to reassure Descartes that as he can clearly and distinctly perceive that his mind is a non-physical thinking substance which is distinct from his extended body, then the mind and the body must really be distinct substances. However, as his ontological argument is not immune to being refuted, there is reason to doubt that the mind and the body really are distinct substances. Descartes’s account of the relation between mind and body is that they do not have mechanistic causal relationships with one another, but that they are intermingled with one another as part of a composite. Yet, Smith and Jones (1986, pg. 59) state that science since Descartes’ time leaves no room for immaterial minds in its explanation of human behaviour. Science tells us that: “macro-phenomena such as the behaviour of human cells are the causal results of micro-phenomena (ultimately, the behaviour of the atoms which constitute the cells).” If we trust and believe what modern science tells us, we must reject Descartes’ claim that human beings have a non-physical mind (Jones and Smith, 1986, pg. 59).


1. Perry & Bratman. (1999), Introduction to Philosophy, Third Edition, Classical and Contemporary Readings, pg. 822.

2. Descartes. (1996), Meditations on First Philosophy, pg. 54.

3. Descartes, Ibid, pg. 54.

4. Descartes, Ibid, pg 56.

5. Descartes, Ibid, pg. 56.

6. Skirry. (2005), Descartes and the Metaphysics of Human Nature, pg. 164.

7. Jones and Smith. (1986), The Philosophy of Mind An Introduction, pg. 59.


Descartes. Edited by Cottingham, J. Meditations on First Philosophy, With Selections from the Objections and Replies, Cambridge: Cambridge University Press, (1996).

Grayling, A.C. An Introduction to Philosophical Logic, Oxford: Blackwell Publishing, (2005).

Gueroult, M. translated by Ariew, R. Descartes’ Philosophy Interpreted According to the Order of Reasons, Vol. II, The Soul and the Body, U.S.A: University of Minneapolis Press, (1985).

Jones, O. and Smith, P. The Philosophy of Mind, An Introduction, Cambridge: Cambridge University Press, (1986).

Mattern, R. in Hooker, M. Descartes, Critical and Interpretive Essays, London: The John Hopkins University Press, (1978)

Patterson. Modern Philosophy Handouts 1-8 on Descartes for University of London BA Intercollegiate 2nd and 3rd year philosophy students, London: University of London, (2008).

Perry, J and Bratman, M. Introduction to Philosophy, Third Edition, Classical and Contemporary Readings, Oxford: Oxford University Press, (1999).

Skirry, J. Descartes and the Metaphysics of Human Nature, London: Continuum, (2005).

Originally, this essay was written by Alexander Rikowski in 12/01/2009, during the 2nd year of his BA degree in Philosophy at King’s College, University of London, as part of the ‘Modern Philosophy’ course that he studied.

Copyright © Alexander Rikowski, November 2011

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