Presuppositional apologetics

Presuppositional apologetics is a form of Christian apologetics, largely Calvinist that asserts that the acceptance of the proposition "God exists" and the truth of the Christian Bible is necessary for making the world intelligible. Presuppositional apologetics usually hinges on the rejection of Thomist apologetics, which attempt to establish logical proofs for the existence of god.

The Transcendental Argument for the existence of God is often considered a claim of presuppositional apologetics.

Critique form Un-Falsifiability

One critique of presuppositional apologetics is that it is committed to the claim "God exists" being true; however, because it asserts that the existence of God is necessary for any belief to be intelligible, it is not possible to falsify the claim. The exchange looks something like this:

Skeptic: What would have to be the case for you to reject the belief that God exist?

Apologist: There isn't anything, because my ability to know anything is conditioned on God existing in the first place. If there were conditions such that God didn't exist, then I wouldn't be able to comprehend God existing, or not existing, or any belief.

The move is a reversion to the belief being primitive. The concern is greater, though, when it comes to the belief about the truth of the Bible.

Critique from Modal Logic

One critique of presuppositional apologetics is that it makes an existential claim (i.e. 'God exist') primitive. It is generally accepted, in logic, that only universal claims (like tautologies) can be primitive.

In modal logic, existential claims about logical possibilities (like 'God exists') are generally believed to be true in at least one possible world and false in some other possible world. Because they are generally accepted as being false in some possible world, they are not considered necessary truths. Only necessary truths can be primitive.