Comparing Knowledge in Descartes’ Meditations on First Philosophy and Hume’s An Enquiry Concerning Human Understanding,
Rationalists would claim that knowledge comes from reason or ideas, while empiricists would answer that knowledge is derived from the senses or impressions. The difference between these two philosophical schools of thought, with respect to the distinction between ideas and impressions, can be examined in order to determine how these schools determine the source of knowledge. The distinguishing factor that determines the perspective on the foundation of knowledge is the concept of the divine.
Descartes is a prime example of a rationalist. Descartes begins his Meditations on First Philosophy by doubting his senses in the first meditation. “From time to time I [Descartes] have found that the senses deceive, and it is prudent never to trust completely those who have deceived us even once”(Descartes: 12). In the second meditation, Descartes begins to rebuild the world he broke down in the first meditation by establishing cogito ergo sum with the aid of natural light. It is with this intuition that the cogito is established, from the cogito, intellect, from the intellect, knowledge; thus knowledge has been defined in this world that Descartes is constructing from scratch. Descartes uses the fact that he is a thinking thing to establish the existence of other things in the world with the cosmological and ontological arguments, as well as a meditation on truth and falsity. “So now I seem to be able to lay it down as a general rule that whatever I perceive very clearly and distinctly is true” (Descartes: 24). Descartes only utilizes his perceptions to establish ideas of the things that he cannot get a picture of because they contain more formal reality than he does. These ideas which must be established with perceptions are limited to the self, Res Cogitans (intellect), and God. Once the certainty of Res Cogitans is developed, clear and distinct perceptions are replaced with clear and distinct ideas. It is these ideas from which Descartes derive knowledge, including the existence of Res Extensa (corporeal things). Therefore, Descartes, a rationalist, derives his knowledge from ideas and reason, all of which stem from an instance of natural light.
The empiricists, however, do not believe in natural light and therefore do not hold knowledge to be derived from these innate ideas. David Hume is one of these empiricists. Hume was a scientist and an atheist; his occupation and beliefs disallowed him from holding innate ideas to be a valid basis for knowledge. In An Enquiry Concerning Human Understanding, Hume points out a...