Both ideas deal with the study of epistemology, which is basically the study of knowledge. Empiricism and Rationalism are opposing sides in the argument of how we acquire knowledge throughout life. Allow me to introduce you to these two ideas about how you know what you know.
This idea explains that everything we know is learned through experience. In other words, the evidence we have for what we know lies within our sensory data — taste, smell, touch, sound and sight. Empiricism explains that there are also no “innate ideas,” or there isn’t any knowledge we can acquire without experiencing it.
John Locke was a popular supporter of empiricism. He claimed that at birth a human being was a tabula rasa — a blank slate. The infant learns, through experience, the knowledge they will hold for the rest of their lives. Picture a blank notebook, everything you experience in life is another mark in that notebook which is represented as knowledge.
This view explains our knowledge-gaining ability in a different light. Rationalism states that everything is learned through reason and deduction. All in all, it’s a more mathematical way of looking at knowledge acquisition. A rationalist would take empiricist ideas and explain that behind all the sensory and emotional data, there are rational explanations that could be made.
Descartes was one of the first to bring about the idea of rationalism. He claimed that the basic principles of reality are all discovered through reason and deduction. In his Meditations on First Philosophy, Descartes arrives at the conclusion that some of our sensory data can lie to us. For example, dreams appear to be real and it seems as if things can happen in our sleeping minds that are improbable in the real world. Experience of these events will not give truth about reality. Using this as a starting point, Descartes deduces through logical analysis that after denying in the belief of everything only reason would lead him to believe in the existence of himself — read the “I think, therefore I am” post for more.
What if I believe in both?
Not to worry. The thing about Empiricism and Rationalism is that the two can be thought of as a pair. Immanuel Kant started off as a Rationalist, but then concluded that both Empiricism and Rationalism were required for human knowledge. His reasoning was that experience is necessary for human knowledge, but reason is needed to process that experience. Although you may come across die-hard empiricists and rationalists that do not think this is the case.
These two topics are quite interesting when you look at them more closely. I only brushed over what these ideas mean, for if I were to go into these topics more deeply it would take up a rather large post. Remember that Empiricism and Rationalism both deal with knowledge acquisition. Where empiricism claims that all knowledge is gained through experience, rationalism claims that we learn what we know through logic. To be completely honest, these terms are beginning to die out. Some contemporary philosophers are claiming that these terms limit the way in which we examine the ancients. Nevertheless, no matter how you think knowledge comes about, keep on thinking, and the knowledge will come along with it.