Routledge History of Philosophy Volume IV

198 RENAISSANCE AND SEVENTEENTH-CENTURY RATIONALISM
things, but he is the author of necessity and possibility; he was ‘just as free to
make it not true that the radii of a circle were equal as he was free not to create
the world’. 64 Some of Descartes’s critics objected that this was incoherent, but
Descartes replied that just because we humans cannot grasp something is no
reason to conclude that it is beyond the power of God. God thus turns out, on
Descartes’s conception, to be in a real sense incomprehensible: our soul, being
finite, cannot fully grasp (French, comprendre; Latin comprehendere) or
conceive him. 65
From Descartes’s insistence on the ‘incomprehensibility’ of God, two
profoundly disturbing problems arise for Cartesian philosophy. The first relates
to Descartes’s attempt to found his scientific system on secure metaphysical
foundations. In the First Meditation, the possibility had been raised that the
human intellect might go astray ‘even in those matters which it seemed to
perceive most evidently’. And the doubt so generated extended, on Descartes’s
own insistence, even to our fundamental intuitions about the mathematical
simple natures. But what of the intellectual simple natures—the fundamental
conceptual apparatus needed for the meditator to arrive at knowledge of his own
existence? We suggested earlier that if the doubt was allowed to go this far, then
the very possibility of the meditator’s achieving any coherent reflection on his
own existence as a conscious being would be foreclosed at the outset. But the
doctrine of the divine creation of the eternal verities seems to entail that even our
grasp of these basic concepts could be unreliable, in the sense that what is
necessary for us may not be necessary for God. A gap is thus opened up between
the basic processes of the human mind, and the true nature of things. And if we
have no reliable hold on the true logical implications of our concepts, if there is
no sure route from what is ‘true for us’ to what is ‘true for God’, the entire
Cartesian journey from indubitable subjective awareness to reliable objective
knowledge seems threatened at the outset.
From this nightmare of opacity, an even more disturbing threat to the
Cartesian project seems to follow. If the structure of the fundamental principles
of logic is not ultimately accessible to human reason, but depends on the
inscrutable will of God, then the very notion of ultimate truth, of something’s
being ‘true for God’, turns out to be beyond our grasp. 66 In his programme for
science, Descartes needs to insist constantly on the immutability and coherence
of the fundamental laws which govern the universe. By appealing to these laws,
we are able, asserts Descartes, to derive a whole structure of necessary
connections which operate in the world, and unravel a complex series of results
which describe the behaviour of matter in motion in accordance with the laws of
mathematics. 67 But now, given that the rationale behind these necessities is
ultimately opaque to us, it seems to follow that the rationally ordered universe
which Cartesian science had hoped to reveal becomes in the end merely a series
of arbitrary divine fiats; and against this background it is hard to see how the laws
of nature could ultimately be construed as anything more than brute regularities.
In short, the doctrine of the divine creation of the eternal truths generates, from