For every event, there is a cause.We can paraphrase this claim in another way:
For every event, there may be a detectable cause, and if there is no detectable cause, then there is an undetectable one.The business of detectable causes is quite uncontroversial, so I'm going to focus on the undetectable ones. Here's the relevant corollary:
Principle of Undetectable Causation:The negation of this can be expressed as:
Every event that has no detectable cause has an undetectable one.
Anti-Principle of Undetectable Causation:The problem with both the Principle and the Anti-Principle is that neither has any epistemic test. No observation can validate either proposition. Seeing caused events backs up neither claim because such evidence concerns detectable causes, not undetectable ones.
There are some events that have no cause, detectable or otherwise.
Given that the rational mind treats like as like, the philosopher cannot rationally justify acceptance of either the principle or its negation because there is no evidence to support either one.
We should not be too surprised to find that wholesale acceptance of such principles is irrational. The root of the problem is in the definition of existence itself.
If I say that a unicorn exists in Sherwood Forest, I am creating a model of a set experiences that are consistent with my claim. Seeing a unicorn in the London city center is not relevant to my claim. Seeing a horse in Sherwood Forest is not relevant to my claim. But seeing a horse with a horn on its head in Sherwood Forest is relevant and consistent with it. And, there may be still other experiences that are incompatible with my claim.
The claim X exists => There is some set of relevant experiences such that the set is divided into two subsets: the subset of possible experiences compatible with the claim, and the subset of experiences incompatible with the claim.(Note that there might be some experiences irrelevant to the claim.)
Now, what if we should discover a horse roaming Sherwood with a plastic horn glued to its head? Do unicorns then exist in Sherwood Forest? It depends. If by unicorn, I meant a genetic unicorn that grew a horn by virtue of its DNA, then no. If I meant something that merely looks superficially like a unicorn, then yes.
What we see here is that the meaning of the existence claim is precisely that set of experiences that satisfy the claim. The two are intimately connected. Many existence claims are somewhat imprecise for this very reason. As in the case of the fake unicorn, we do not always anticipate or articulate every possible relevant experience, and even the things we mean to say are often imprecise.
Given the relationship between the meaning of a claim and the experiences that satisfy it, we must conclude that any two existence claims that apply to the same set of experiences, and which subdivide that set in the same way, are actually the very same claim.
This sets us up for the final blow: if an existence claim and its negation are relevant to and consistent with the same set of experiences, then the claim has no truth value at all. If it were true, then its negation would also be true because they both mean the same thing.
We can see that this is true of the Principle of Undetectable Causation, and that the Principle can be neither true nor false. As a proposition, the Principle is meaningless. It literally says that:
P = We have some specific set of relevant experiences, and every element of that set is compatible with this statement.and its negation says the very same thing. If the Principle means something, it is not as a proposition.
Likewise, when we say that "the existence of God is compatible with every possible experience," we actually mean precisely the same thing as "the non-existence God is compatible with every possible experience." So neither "God exists" nor "God does not exist" are meaningful as propositions.
After subtracting out the naughty bits, what is left of the Principle of Sufficient Reason? This:
For every event, there may be a detectable cause.Hey, I can agree with that!