Saturday, 1 January 2011

Some New Year thoughts on presuppositional logic

"Logic" is part and parcel of the nature of existence. How do I know my reasoning has any validity? Simple: I am aware that logic exists. Therefore I can rely on logic when I use reason as a path to knowledge. How do I know logic exists? The fact that I know anything at all is an indication that the underlying logic of reasoning is valid.

I can assume my reasoning is valid, because if I wasn't able to do it I wouldn't be able to make that assumption. Assuming things is part of the act of reasoning.

Presuppositionalists, however, claim that reasoning is only possible because God exists. They assume that if God hadn't created logic we wouldn't be able to reason, and that because we can reason, therefore God exists.

But logic isn't something separate and above the universe. Logic is not transcendent, it's merely a description of an aspect of the universe as we experience it. Asking whether there are absolute laws of logic is akin to asking if there's an absolute universe. It's like asking if there is matter and energy that is somehow "outside" the matter and energy of the universe, or "beyond" space and time. You might as well ask what happens when an irresistible force hits an immovable object, or what is the mathematical formula for the area of a square circle, or what's the marital status of a married bachelor. These questions don't make sense, and just because they can be asked doesn't mean they have answers. They don't.

Presuppositionalists claim that unbelievers have no basis for assuming that  their reasoning is valid, because (they say) we use unvalidated reasoning in an attempt to validate itself. On the other hand, presuppositionalists assume their reasoning is valid because reasoning was created by God. This, of course, presupposes the existence of God, and is the ultimate God-of-the-gaps argument: the only way that reasoning will work is if it was created by God — therefore God exists. But I would throw the presuppositionalists' question back at them: how do they know that their reasoning is valid? It isn't enough to say that God created reasoning, or even to say that there exist absolute laws of logic that transcend the universe. How do they know that? How do they know that such knowledge is true?

The truth is, they don't.
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