194 ARGUMENTS: MONOTHEISTIC CONCEPTIONSBut a world of which B was true is a world of which C could not be true.
Hence inferring from A to B is fallacious.^22 Inferring from (a) to (b) is
tantamout to inferring from A to B. If Aquinas either inferred from (a) to (b),
or simply did not adequately distinguish between them, the argument fails.
Inference two: from D to E
D Everything at some time fails to exist.
E Sometime, everything fails to exist.^23
Everything is green at some time or other does not entail At some time or
other, everything is green. Similarly, D does not entail E. Again, the
inference from (a) to (b) is tantamount to inferring from D to E. If Aquinas
either inferred from (a) to (b), or simply did not adequately distinguish
between them, the argument fails.
The gist of these criticisms is that even if at some time or other, each thing
that exists will pass out of existence, it does not follow that they will all pass
out of existence at the same time, and so long as earlier members can
generate later ones, things will go on. If Aquinas is not entitled to infer from
(a) to (b), then even if he is entitled to infer from (b) to (c) this will not help,
since he has no legitimate way to get to (b).
Aquinas is also criticized for claiming that the alleged time at which
everything would simultaneously pass away would already have occurred;
why not regard the proof (if it did succeed) as proving that at some future
time there will not be any generable things? His answer is that if there have
been generable things for only a finite time past, then there had to be a cause
of there coming to be generable things and so there is something that is not
itself a generable thing, and if there have always been generable things, then
an infinite time has passed and in any infinite time we would have reached
the time at which everything has passed away. We can afford not to enter
into this controversy.^24
The first three of Aquinas’s Five Ways begin by reference to the fact that
things exist that might not have existed and that depend for their existence
on something else, and that things change. They then require some such
claim as What can depend for its existence on something else does depend for
its existence on something else and What changes is changed by something
else, as well as such claims as If there are things that exist that depend for
their existence on something else, then there is something that exists
independent of anything else and If things are caused to change by
something else, then there is something that causes change without itself
ever changing. In part for reasons given as we explained these arguments,
none of them constitutes a proof that extends our knowledge. Thus the results of