Descartes: A Biography

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 Descartes: A Biography

take the liberty to attribute this matter and extension to the soul, for that is nothing

more than conceiving of its union with the body. (iii.,)

Despite the obscurity of these suggestions, this is as close as Descartes had

ever come to addressing the apparent inconceivability of an immaterial

mind acting on a material body, and vice versa, when the two interacting

entities are defined in such a way that they have no common properties.

As one might expect, Descartes’ acute correspondent returned to the

same question within a matter of days. She wrote (July) about a

problem that had already been raised in a number of the objections to the

Meditationsand to which Descartes had formulated a reply that satisfied

none of his critics. Elizabeth pointed out that, according to Descartes’ own

analysis in theMeditations, the main reason why we make mistakes and

hold false beliefs is that our judgments overstep the evidence that supports

them or, in her words, that we make judgments ‘about things that we do

not perceive adequately’ (iv.). When Descartes constructs a theory of

mind, therefore, he may feel confident that there is no overlap between

the concepts of extension and thought. However, it is still possible that,

despite his best efforts to think about these realities clearly, there is a covert

relation between thought and extension that he has simply failed to notice.

‘Although extension is not necessary for thought...it may contribute to

some other function of the soul which is no less essential to it’ (iv.).

The obvious person to have raised this objection was Thomas Hobbes.

In his objections to theMeditations, the English philosopher had pressed

the suggestion that thought is nothing more than some complex physical

activity, and that Descartes was mistaken in claiming that thinking is

really distinct from all bodily processes. Descartes’ unsympathetic reply

to Hobbes was that we do not know whether thinking is or is not explained

bycomplex brain processes. Rather than jump to conclusions, therefore,

he suggested that the question be deferred until we can provide some

plausible account of how processes in the senses and the central nervous

system result in the experience of thinking. Meantime, we should talk

about the subject that supports the activity of thinking and the subject

that supports properties that are known to be physical, and we should

decide later whether these are two distinct subjects or the same reality

under different descriptions. ‘It is very reasonable and in keeping with

common usage that we apply different names to those substances that

werecognize as the subjects of completely different acts...and that we