It claims that apart from presuppositions, one could not make sense of any human experience, and there can be no set of neutral assumptions from which to reason with a non-Christian. Presuppositionalists claim that a Christian cannot consistently declare his belief in the necessary existence of the God of the Bible and simultaneously argue on the basis of a different set of assumptions that God may not exist and Biblical revelation may not be true. Two schools of presuppositionalism exist, based on the different teachings of Cornelius Van Til and Gordon Haddon Clark. Presuppositionalism contrasts with classical apologetics and evidential apologetics.