Routledge History of Philosophy Volume IV

DESCARTES: METAPHYSICS AND THE PHILOSOPHY OF MIND 195
THE ROLE OF GOD
It is scarcely possible to underestimate the role played by God in the
development of Descartes’s foundational project. The meditator’s awareness of
his own existence is a curiously transitory insight: I can be sure I exist only so
long as I am thinking. 48 Admittedly, my awareness of myself as a thinking thing
is quite indubitable and transparent: it surely could not turn out, Descartes
observes, that ‘something I perceived with such clarity and distinctness was false ’ ;
and yet the earlier suggestion that an all-powerful God might make me go wrong
‘even in those matters which I think I see utterly clearly with the mind’s eye’
gives me pause for doubt. Although I have found one unshakeable truth, no
general progress towards a systematic structure of knowledge will be possible
unless I remove this residual doubt and establish ‘whether God exists and, if so,
whether he can be a deceiver’. 49
Deprived, at this stage of his inquiries, of any certain knowledge of the outside
world, the Cartesian meditator has to establish the existence of God drawing
purely on the resources of his own consciousness. This is done by making an
inventory of the ideas found within the mind. We cannot know at this stage
whether our ideas correspond to anything real, but it is clear that they are ‘like
images of things’: that is, they have a certain representational content. 50
Descartes now reasons that the content of each idea must have a cause; for
nothing can come from nothing, yet ‘if we suppose that an idea contains
something which was not in its cause, it must have got this from nothing’. In
most cases, the content of an idea presents no great explanatory problem: the
content of many of my ideas, observes Descartes, could easily have been drawn
from my own nature; other ideas (like those of unicorns) are simply fictitious, or
made up—put together by my own imagination. But the idea that gives me my
understanding of ‘a supreme God, eternal, infinite, immutable, omniscient,
omnipotent and the creator of all things’ is different: ‘all these attributes are such
that the more carefully I concentrate on them, the less possible it seems that they
could have originated from me alone.’ So the idea of God must have, as its cause,
a real being who truly possesses the attributes in question. In creating me, God
must have ‘placed this idea within me to be, as it were, the mark of the craftsman
stamped on the work’. 51
Of the many problematic features of this argument, the most striking is the
extent to which it relies on what are (to the modern ear at least) highly
questionable assumptions about causation. A swift reading might suggest that all
Descartes needs is the (relatively uncontroversial) deterministic principle that
everything has a cause (which Descartes expresses as the maxim that ‘Nothing
comes from nothing’). But in fact the argument requires much more than this: it
is not just that my idea of God needs a cause, but that its cause must actually
contain all the perfection represented in the idea. It is ‘manifest by the natural
light’ claims Descartes, that ‘there must be at least as much reality in the cause
as in the effect’, and hence ‘that what is more perfect cannot arise from what is