Descartes: A Biography

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 Descartes: A Biography

terms of which we structure our thinking. Thus there is one basic concept

available for thinking about the mind, namely, the concept of thought; and

there is one basic concept that must apply equally to all bodies, namely, the

concept of extension. It would therefore be a mistake to confound these

concepts, since they are equally basic, and it would also be misleading to

think about any reality whatever by applying the wrong concept. The same

kind of conceptual embargo applies when thinking about the interaction

of mind and body. ‘We have confused the notion of the soul’s power to act

onthe body with the power by which one body acts on another’ (iii.).

Descartes advised, rather, that Elizabeth not think of the mind acting on

the body by analogy with one body colliding with another. She should

conceive of the way in which the mind affects the body in a completely

different way.

Elizabeth found this reply unsatisfactory. She made excuses for her

failure to understand Cartesian philosophy by referring to the unwelcome

distractions and unavoidable duties of her social life. It is clear, however, not

that she had failed to understand, but that Descartes had failed adequately

to address the problem she raised. Descartes had hoped to explain how

the mind moves the body by analogy with the way in which gravity moves

bodies towards the centre of the Earth, because no one is tempted to

think of gravity as another body that pushes heavy bodies by impact. In a

similar way, he suggested, one might think of the mind causing the human

body to move without being itself another body that moves by impact. On

Descartes’ own acknowledgement, however, the proposed analogy was

unhelpful because it tried to resolve a problem by analogy with something

else that we do not understand. Elizabeth presses home her objection: ‘I

confess that it would be easier for me to attribute matter and extension to

the soul than to attribute the ability to move a body, and to be moved by a

body, to an immaterial being’ (iii.).

Descartes’ reply to this letter (June) includes a surprising demo-

tion of the role of metaphysics in resolving problems encountered in phi-

losophy. He acknowledges that he had never spent more than a few hours

adayin thinking about things by using his imagination, nor had he given

more than ‘a few hours a year’ to thoughts that occupy the understand-

ing on its own, although the latter is evidently what is involved in doing

metaphysics.He returns to the same suggestion at the conclusion of his

letter, in a passage that is so at odds with the standard image of Descartes, as

an apologist on behalf of ‘pure reason’, that he might almost be suspected