In this post, I want to help make it clear exactly what Malpass's objections are, and more importantly, what Slick would have to do to avoid them. For understanding what Slick has to argue to avoid the objections shows the deeper problem with his entire approach.
On his podcast, Slick presented the basic argument as follows:
“...So we have 'God and not-God'. So that's called a true dichotomy. We've got either 'God exists' or 'it's not the case that God exists'... Let's take the no-God position. Can the no-God position account for the transcendental laws of logic? And the ultimate answer is, no it cannot. So therefore, because it cannot, the other position's automatically necessarily validated as being true.”
What Slick is trying to do here – as he himself has often stated – is present a disjunctive syllogism, that is, an argument with the form:
p or q
not q
therefore, p
In addition, he states that his first premise is a dichotomy – that is, that it has the form “p or not-p” – which means that it covers all possibilities, and is therefore necessarily true. That way, he has no need to argue for it.
As he states it, however, his argument is a mess, and so it takes a bit of work to turn it into a disjunctive syllogism. Taken at face value, he appears to be arguing,
1. Either God exists or God doesn't exist
2. Atheism cannot account for the laws of logic
3. Therefore, God exists.
But to begin with, this isn't a disjunctive syllogism; the second premise is not the negation of one of the disjuncts in the first premise. And what's worse is that, as it stands, this argument is clearly invalid.
To turn it into a disjunctive syllogism, we can instead restate Slick's argument as something like the following:
1. Either God accounts for the laws of logic or something else accounts for the laws of logic
2. It is not the case that something else accounts for the laws of logic
3. Therefore, God accounts for the laws of logic.
But now there is a problem with Slick's claim that his first premise is necessarily true. In the above argument, premise one is not a dichotomy. To think so is to confuse:
(A) “Either God accounts for the laws of logic or something else accounts for the laws of logic”
with:
(B) “Either God accounts for the laws of logic or God does not account for the laws of logic.”
Statement (B) is a dichotomy; statement (A) is not, for it does not cover all possibilities. For instance, it ignores the possibility that nothing accounts for the laws of logic.
Now, as it turns out, Slick actually should not be aiming at having a dichotomy as the first premise of his argument. He may think that is the way to go, so as to avoid having to argue for the premise. But as Malpass pointed out, if the first premise were a dichotomy, the argument would simply beg the question. To see why, suppose that we substitute (A) with (B) in the above argument, so that Slick would be arguing something like this:
1. Either God accounts for the laws of logic or God does not account for the laws of logic
2. It is not the case that God does not account for the laws of logic
3. Therefore, God accounts for the laws of logic.
The problem with this is that now the conclusion is just a restatement of the second premise. To say that it is not the case that God does not account for the laws of logic is simply to say that God does account for the laws of logic. In other words, the form of this latest argument is:
p or not-p
not not-p
therefore, p
But to say “not not-p” is just to say “p,” and so the argument becomes:
p or not-p
p
therefore, p
And that's not exactly a good argument.
(There is a more general problem here that Malpass didn't get into, namely, that anytime there is a logically true statement in an argument – like “p or not-p” – it can be removed without altering the argument's validity. Logical truths are not really needed to make arguments go through. This is why the first premise above is redundant, and that all that Slick would be arguing in this case is “p, therefore p.”)
So what can Slick do?
Well, he could try to keep (A) as the first premise and simply stop claiming that it is a dichotomy. However, he now needs to provide us with reasons for accepting that premise.
Let's consider that argument again:
1. Either God accounts for the laws of logic or something else accounts for the laws of logic
2. It is not the case that something else accounts for the laws of logic
3. Therefore, God accounts for the laws of logic.
This first premise is really just saying that something accounts for the laws of logic (whether that is God or not). The argument would therefore be clearer if stated as follows:
1. Something accounts for the laws of logic
2. But if God did not exist, nothing would account for the laws of logic
3. Therefore, God exists.
What Slick must do, then, is show that something must account for the laws of logic (as well as that without God, nothing would). And that's the deeper problem that I alluded to at the beginning.
Now, as Slick himself has said, what he is referring to when he talks about what accounts for logic are the “necessary preconditions” for the existence of logical truths. Or, to put it another way, what must be the case if there are to be logical truths.
One mistake Slick and other presuppositionalists make – though they are certainly not alone in this – has to do with how they understand the relationship between logical laws and that to which they apply. Given the way he argues, Slick must maintain that a rock (say) would not be identical to itself without something else, namely the “law of identity,” making it the case that the rock is identical to itself. But that's simply confusion. That rock is that rock, and that's all it takes for it to be identical to itself. There doesn't have to be in addition a logical truth that brings this fact about, and which in turn has to be accounted for.
Presuppositionalists then compound their mistake by imagining that the logical laws can only exist in the mind of God – which if anything is an even greater confusion.
Logical laws merely describe what must be the case. And since the truths they describe are necessary, there is nothing that they depend on, or even that they could possibly depend on. So not only is God not needed to account for them, but to think that God can account for them is incoherent. Slick's entire approach, then, is misguided.
If I had the opportunity, I'd ask Slick if he thinks it is even conceivable that logical truths could fail to hold. Does he, for example, think that (in a godless world) a rock might at the same time both exist and not exist? Or that it might be the case that all human beings are mortal, and that S is a human being, but that S is not mortal?