Today a somewhat prevalent impression links Aristotle and Aquinas as though they both represented the same general type of philosophical thinking. Prima facie indications, it is true, may seem to point in the direction of a unitary trend in their basic philosophical procedures. Aquinas uses Aristotle's formal logic. Both of them reason in terms of actuality and potentiality; of material, formal, efficient, and final causes; and of the division of scientific thought into the theoretical and the practical and productive. Both regard intellectual contemplation as the supreme goal of human striving. Both look upon free choice as the origin of moral action. Both clearly distinguish the material from the immaterial, sensation from intellection, the temporal from the eternal, the body from the soul. Both ground all naturally attainable human knowledge on external sensible things, instead of on sensations, ideas, or language. Both look upon cognition as a way of being in which percipient and thing perceived, knower and thing known, are one and the same in the actuality of the cognition.