Every given reality implies the thought which apprehends it. Therefore being is the condition of knowing; knowing is not the condition of being. - Étienne Gilson

What, then, will this philosophy be? Thomas only employed it for the service it renders Christian wisdom. No doubt this is why he never thought of separating it from this wisdom and giving it a name. He probably did not foresee that the day would come when people would go through his works to extract the elements of a philosophy from his theology. He himself never attempted this synthesis.

What is most apparent and constant in Thomas' personality, the image he most likely had of himself, is the teacher. The saint was essentially a Doctor of the Church; the man was a teacher of theology and philosophy; the mystic never entirely separated his meditations from his teaching, which drew its inspiration from them.

While Descartes finds being in thought, Saint Thomas finds thought in being.