  Although Descartes recognized an important role for the senses in  natural philosophy, he also limited the role of sense-based knowledge by comparison with Aristotelian epistemology. According to many scholastic Aristotelians, all intellectual content arises through a  process of intellectual abstraction that starts from sensory images as present in the faculty of imagination. Mathematical objects are formed by abstraction from such images. Even metaphysics rests on knowledge derived by abstraction from images. Of course, in this Aristotelian scheme the intellect plays an important role  in grasping mathematical objects or the essences of natural things through considering images. By  contrast, Descartes affirmed that the truths of mathematics and metaphysics are grasped by the intellect operating independently of the senses and without need for assistance from the faculty of imagination. Descartes designated the exercise of the intellectual  capacity apart from sense-based images the use of the  “pure intellect.”