Atheism and Theism 119is a time when it does not exist, then there would be a time when nothing
exists’. [ (∀x) (∃t) (x does not exist at t) therefore (∃t) (∀x) (x does not exist
at t) ]. This is indeed a fallacy but it is not St Thomas’s reasoning. Look
carefully at the text.
The proof begins with a distinction between two types of existent, the
contingentand the necessary, between that which is but might not have been,
and that which could not possibly not exist. The former type is then shown to
be instantiated by reference to things observed to be generated and destroyed.
Next comes the supposed fallacy. Aquinas argues as follows:
1 A thing that has come into being did not exist at a prior time.
2 If everything were like this, then there was a time when nothing existed.
3 If that were so there would be nothing now (because contingent things
require a cause and if previously there were nothing then what now exists
could not have been caused to be).
4 There are contingent things existing now, therefore it is not the case that
there was a time when nothing existed, and therefore not everything has
come into being, not previously having existed.
The standard criticism is that the passage from (1) to (2) involves the
fallacy I mentioned. But the point Aquinas is making only involves time(s)
because of his characterization of the contingent in terms of coming into
existence, i.e. temporal generation. He is not arguing ‘for each there is a
time therefore there is a time for all’; but reasoning that if each were of
the kind ‘temporally generated’, i.e. contingent, then there never would have
been anything: in other words (2) generalizes the point introduced in (1).
Temporally generated beings require a pre-existent cause, hence not every-
thing that exists can be of the temporally generated sort. His claim, if it
is correct, cannot be met by saying let there be, for each temporally gener-
ated being, a parent that is itself a generated being. That leaves the general
problem of contingency untouched. So, there must be some non-contingent
thing or things. Notice that at this point Aquinas does not attempt to
derive the existence of a single ultimate cause. Having concluded that not
everything can be contingent, he allows that those which are not may be
either dependently or non-dependently necessary. Next, however, he refers us
back to the previous argument concerning causal series and concludes that on
the basis of parallel reasoning we must postulate an unconditionally necessary
first cause.
The core issues in these proofs are those of existential and causal depend-
ency. Such themes place them firmly within the tradition of cosmological
speculation as to why there is anything rather than nothing and what the
source of the universe might be. Before discussing these matters further let