 Maritain held that philosophy was an ancilla theologiae (“handmaid of theology”), and that philosophy, under the rubric of metaphysical knowledge, allows for the demonstration of a number of basic religious beliefs. Like Aquinas, Maritain accepted the classical foundationalist position that these beliefs could be established by rational deduction from self-evident principles and constituted genuine knowledge. Specifically, he held that, by the use of natural reason, one can come to know certain truths about God, and that the ‘five ways’ of Thomas Aquinas provided sure knowledge of God’s existence. But Maritain also argued that there could be other ‘proofs’ of the existence of the divine and, in Approches de Dieu (1953), he developed what he called a “sixth way”.