Descartes: A Biography

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The Quarrel and Final Rift with Regius 

set out his metaphysical views about human nature, under the title:A

Brief Explanation of the Human Mind or the Rational Soul, in which is

explained what it is and what it may be. The subtitle indicated that it had

been ‘formerly proposed for public examination and was now significantly

clarified by the work of Henricus Regius of Utrecht and claimed by the

notes of the very noble Descartes’. The book carried a dedication to the

‘Very Noble Rene Descartes’, which must have aggravated the situation ́

still further.

This pamphlet included the same theses about the human mind that

had already alienated Descartes inand. They were numbered

foreasy reference, on this occasion, and the starkness with which they

were expressed, with a minimal commentary, confirmed the danger of

misinterpretation that had concerned Descartes in their earlier manifes-

tations. For example, the second thesis reads: ‘As far as the nature of

things is concerned, it seems possible for the soul to be either a substance

or the mode of a corporeal substance.’Regius concludes, with an obvious

though implicit reference to Descartes: ‘therefore those who claim that

wecan clearly and distinctly conceive of the human mind as necessarily

and really distinct from the body are mistaken.’Besides, ‘the fact that we

can doubt the body even though we cannot truly doubt the mind does not

prevent the mind from being a mode of the body.’As in his earlier, more

complete version of this argument, Regius adds for good measure that ‘in

order to think, the mind does not need any innate ideas, notions, or axioms

that are distinct from the faculty of thinking,’ and that ‘the idea of God,

which exists in our mind, is not a sufficiently valid argument to prove the

existence of God.’It was a calculated irony on his part to dedicate this

tract to Descartes and to acknowledge with an ambiguous term, on the

title page, that it was either claimed by Descartes as his own or repudiated

byhim as the exact opposite of some of his main theses in metaphysics.

Descartes made one final contribution to this intractable dispute, when

he summarized the history of the row with Voetius inThe Apologetic Letter

to the Magistrates of Utrechtin February(discussed in Chapter).

Thought in Animals

Descartes’ anatomical investigations continued during, despite his

frustrating failure to complete the outstanding research required for the

missing sections of thePrinciples.Hedescribes experiments that involved