its immediate successor, there still would need to be a cause of the entire infinite
succession.
It is at this point that David Hume (1980), writing about half a century after Clarke,
raised what is considered by many to be a decisive objection to Clarke's argument. He
claimed that for any aggregate, whether finite or infinite, if there is for each of its
constituents an explanation, there thereby is an explanation for the entire aggregate. Thus,
if there were to be an infinite past succession of contingent beings, each of which
causally explains the existence of its immediate successor, there would be an explanation
for the entire infinite aggregate, and thus no need to go outside it and invoke a necessary
being as its cause. Hume's claim that explanation is in general agglomerative can be
shown to be false (see Gale 1991; Pruss 1998). For it is possible for there to be a separate
explanation for the existence of each constituent in an aggregate, say each part of an
automobile, without there thereby being an explanation of the entire aggregate, the
automo
end p.122
bile. The explanation for the latter would be above and beyond these several separate
explanations for the existence of its constituent parts, as, for example, one that invokes
the assembling activity in a Detroit factory.
William Rowe (1975) has given a variant version of Clarke's argument. He chooses as his
initial contingent existential fact that there exists at least one contingent being. This is the
plaintive cry that one might hear in a coffeehouse, “Why is there something rather than
nothing?”, to which, according to Sidney Morgenbesser, God's response is, “Look, you
guys, suppose I created nothing, you still wouldn't be happy.” The point of
Morgenbesser's witticism is that even if there were to be nothing, that is, no contingent
beings, the PSR still would require that there be an explanation for this big negative fact.
The PSR is an equal-opportunity explainer, not giving a privileged status to positive
reality. We ask “Why is there something rather than nothing?” simply because there
happens to be something rather than nothing. The PSR requires there be an explanation
for the contingent fact that there exists at least one contingent being. It cannot be given in
terms of the causal efficacy of another contingent being, since this would result in a
vicious circularity. Thus, it must be in terms of the causal efficacy of a necessary being.
This completes our brief survey of traditional cosmological arguments. It is now time to
critically evaluate them. It was seen that each faced an unresolved gap problem consisting
in its failure to show that the first cause, unmoved mover, or necessary being has all of
the essential divine attributes. The most serious form the gap problem takes concerns the
moral qualities of this being. Here the problem of evil has been appealed to by the likes
of Hume to argue that probably it is not an all-good but rather a morally indifferent being.
This, no doubt, is the point of a bumper sticker that reads, “God does exist. He just
doesn't want to get involved.” To counter the challenge of evil, it is necessary to construct
theodicies for the known evils and give convincing design arguments, which is the topic
of the next section.
The most vulnerable premise in these arguments is its PSR, whether in its universal or
restricted form. It is imposing on the nontheist opponent of these arguments to ask him or
her to grant that every true contingent proposition (or some restricted set of them)