Descartes: A Biography

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The Principles of Philosophy() 

body in question has changed into a different reality despite the fact that

none of its properties has changed. However, we have still no reason to

call it anything other than wine, based on the only criteria available for

applying different names to different things, which are their observable

qualities.

Baillet had commented in another context that, in constrast with

Sorbi`ere, ‘Mr. Descartes did not have the gift of dissimulation’.It is

difficult to avoid the conclusion here that Descartes is avoiding saying

explicitly what he believes and that he is implying the opposite of what

was taught by Catholic theologians at the time. They standardly claimed

that the observable properties of bread and wine remain unchanged while

the unobservable, underlying substances are changed. Someone as well

informed as Mersenne had even based one of his arguments in natural

philosophy on this reading of the Council of Trent. InThe Impiety of

Deists,hehad argued that each body must be a substance in its own right

and have its own characteristic form. Otherwise, two distinct bodies would

be only one substance, and the church’s teaching about transubstantia-

tion would be undermined unless each body is a distinct substance.

This unwise intervention by Descartes into an insoluble theological

problem was one of the reasons why the Vatican condemned his work

in.

Reactions to thePrinciples

The favourable response to thePrinciplesthat Descartes expected from

French Jesuits did not materialize, and the reactions of other readers were

equally mute or critical. For example, Gassendi was unlikely to be among

the fans of the new book. When asked by Rivet what he thought of it,

he declined to comment on Descartes’ physics as he had done, with con-

tentious results, on his metaphysics. ‘However, I shall add the following, so

that you can think of me as dealing with you in confidence, that this work

will be seen to be extremely empty when it is seen to die before its author.

I certainly do not know anyone who has the courage to read it from cover

to cover who does not find it extremely tedious, and who is not amazed

that it contains such time-consuming trifles.’

The Cavendish brothers were more positive in their assessment, though

probably less well informed. William Cavendish had been head of a reg-

iment in the battle of Marston Moor, in July, and was frustrated