Recently, we have concocted a new version of Clarke's cosmological argument that
manages to make do with a very weak version of the PSR that requires only that for every
contingently true proposition it is possible that it have an explanation, thereby making it
more difficult for the argument's nontheist opponent to reject the PSR premise. Thus, it is
not required that the proposition reporting the existence of the universe comprised of all
the contingent beings there are actually have an explanation, only that it is possible that it
does.
end p.124
Once our opponent has granted the following weak version of the PSR
W-PSR. For every contingently true proposition, p, there is a possible world w that
contains the propositions p, q, and that q explains p.
we are able to deduce from it the strong version of the PSR, namely,
S-PSR. For every contingently true proposition, p, there is a proposition q and that q
explains p.
in which a possible world is a maximal, compossible conjunction of abstract propositions.
It is maximal because for every proposition, p, either p is one of its conjuncts or not-p is;
and it is compossible in that all of its conjuncts could be true together. This deduction,
which is due to Pruss, goes as follows:
- For every contingently true proposition, p, there is a possible world w that contains the
propositions p, q, and that q explains p. W-PSR. - p is contingently true and there is no explanation of p. Assumption for indirect proof.
- There is a possible world w that contains the propositions (p and there is no
explanation of p), q and that q explains (p and there is no explanation of p). From 1 and 2. - In w, q explains p. True because explanation distributes over a conjunction.
- In w, proposition p both does and does not have an explanation. From 3 and 4.
- It is not the case that p is contingently true and there is no explanation of p. From 2–5
by indirect proof. - It is not the case for any proposition p that p is contingently true and there is no
explanation of p. From 6.
Once we have established by this deduction that there actually is an explanation for the
existence of the universe, we show by a series of deductions, which cannot be gone into
here, that it is in terms of the free intentional actions of a very intelligent and powerful
necessarily existent supernatural being. It must be a necessary being because the universe
contains all the contingent beings there are. Because this necessarily existent being freely
creates the universe, our argument escapes Schopenhauer's objection to the cosmological
argument as being like a taxicab that we hire and then dismiss when we have reached our
destination. For the cosmological arguer begins by demanding, on the basis of the PSR,
an explanation for a certain contingent existential fact, but when she arrives at our desired
destination, God, she dismisses the PSR because she does not require an explanation for
the fact that God exists and causes the existence of this fact.
Because our explainer is a necessary being, it is a self-explaining being in the sense that
there is a successful ontological argument for its existence, even if we aren't smart