Descartes & Hume Essay

Rene Descartes was a rationalist, meaning he thought that reason alone, not sensation or experience, was the source to attaining knowledge about the eternal truths of the universe, such as mathematics, epistemology, metaphysics and the existence of God. He excluded physics from this list, admitting that knowledge of physics only comes through experience (Descartes). Regardless, his rationalistic epistemology made it so that Descartes could only accept the truth about something if it was based upon a principle that was clearly and distinctly certain. Innate, a priori knowledge is fundamental to Descartes philosophy. A priori refers to any knowledge that is attained without appealing to sensation (O’Connor, Class Notes). Being a rationalist, he completely doubted every sensory experience he had ever had. Sensation is ever-changing and sometimes misleads or deceives us, so according to Descartes, trusting in an experience of sensation to provide us with any kind of universal truth would be foolish (Descartes). Whereas rationalism directly focuses on reason as being the only way to attain knowledge about the world, empiricism concentrates fully on all knowledge being a posteriori, or attained through experience and sensation. In an obvious way, David Hume’s empiricist epistemology directly contrasted Descartes rationalism, specifically by how he believed humans can attain knowledge. According to Hume, humans understand the world by experiencing different perceptions: impressions/sensations and ideas/thoughts. The amount of force and vivacity of the perception allows humans to differentiate between the two. Impressions and sensations are more forceful and lively since they are a product of direct experience. Ideas and thoughts are simply weak recreations of the original impressions that were perceived. While Descartes believes that certain ideas are innate, such as the existence of God, Hume absolutely denies the possibility of innate ideas. He claims that humans could never fully know or comprehend anything beyond our impressions. If an impression is not perceived, then it cannot be acknowledged. Since our knowledge is limited to the impressions we perceive, we have no real way of comprehending causality, instead it is often confused with correlation. Cause and effect events tend to occur in close temporal order, but that does not mean we can know whether those events are intrinsically related or not. Instead, we can only place our faith in the customs and habits of human life. Oppositely, Descartes believed we gain knowledge a priori, and we can only know that which we have clear and distinct justification for. In order to justify what we know, we cannot appeal to anything except for reason. Lastly, we must judge those justified ideas by applying Descartes’ specific and logical method of reflection. Thusly, by accepting Descartes’ method, the universal and eternal truths of the world can be known.