Routledge History of Philosophy Volume IV

DESCARTES: METAPHYSICS AND THE PHILOSOPHY OF MIND 197
to prove God exists, since it is impossible to doubt these so long as we are
actually attending to them. 59 Unfortunately, however, the premises of
Descartes’s proofs for God seem to rely (suggested above) on a host of complex
presuppositions which have to be taken on trust: the transparent, self-confirming
quality which Descartes relied on to reach awareness of his own existence is
simply not available in the elaborate causal reasoning needed to establish the
existence of a perfect non-deceiving God. If this is right, then Descartes’s
metaphysical project must be counted a failure: the journey from indubitable
subjective self-awareness to systematic objective knowledge cannot be
completed. The challenge which Descartes puts into the mouth of an imaginary
objector in his dialogue The Search for Truth seems both apt and unanswerable:
You seem to me to be like an acrobat who always lands on his feet, so
constantly do you go back to your ‘first principle’. But if you go on in this
way, your progress will be slow and limited. How are we always to find
truths such that we can be as firmly convinced of them as we are of our
own existence? 60
THE ETERNAL VERITIES
The central place of God in Cartesian metaphysics should by now be more than
clear. But no account of this relationship would be complete without some
attention to one of Descartes’s most perplexing doctrines —that of the divine
creation of the eternal truths. This is a doctrine which does not emerge explicitly
in the Meditations, but it surfaces in the Replies to the Objections, and Descartes
appears to have held it consistently throughout his life. He is reported to have
insisted on it in an interview held two years before his death, 61 and he explicitly
asserted it, in his correspondence, as early as 1630:
The mathematical truths which you call eternal have been laid down by
God and depend on him no less than the rest of his creatures…. They are
all inborn in our minds just as a king would imprint his laws on the hearts
of all his subjects if he had enough power to do so. 62
Traditional theology maintained that divine omnipotence does not entail the
power to do absolutely anything, if ‘anything’ is taken to include even what is
logically impossible. God cannot, on pain of absurdity, do what is selfcontradictory
(e.g. make something which is both three-sided and a square); his
supreme power operates, as it were, only within the sphere of the logically
possible. 63 One might suppose that it is hardly an objectionable limitation on the
power of God that he cannot do nonsensical and incoherent things like creating
three-sided squares; but Descartes’s conception of the deity is of a being of
absolutely infinite power—a being who is immune to any limitation which the
human mind can conceive. Thus, not only is he the creator of all actually existing