: I argue that for Aquinas philosophy is a necessary tool of theology and that philosophy is not changed by its theological context. Rather, the subalternation of disciplines results in a reciprocal relation between philosophy and theology. This is understood in terms of the distinction between what is better known in itself and what is better known to us. This view is defended by (1) reinterpreting Aquinas' use of the metaphor of the water of philosophy being transformed into the wine (...) of theology; and (2) his position that the theological use of philosophy is an instance of grace perfecting nature. (shrink)