Rationalism or Empiricism?

Anannya Uberoi
4 min readDec 22, 2019


Epistemology, or the theory of knowledge, is a branch of philosophy that investigates the nature of knowledge, the relation between knowledge and truth, and the origin of beliefs. It is derived from the Greek word ‘epistēmē’ meaning ‘knowledge’.

The introductory lessons in my epistemology course brought about the primary difference between words like truth, belief and knowledge. It shaped the primary concepts and prerequisites necessary for understanding the views of famous philosophers and what they had to say on the subject. I was surprised to find my belief in the objectivity of knowledge destroyed within the first half an hour of the lecture, as knowledge assumed a completely different meaning and purpose.

The age-old questions of philosophy, such as how to define knowledge, where does knowledge come from, is knowledge possible, how can we know and how does knowledge relate to truth, gain special momentum in today’s times where every question that comes to the mind can be simply looked up online with results displayed in a matter of seconds. With millions of resources and an overflow of information, it is hard to discern between genuine sources and the false ones. This brings another vital question:

How is a source credited as being genuine after all?

Since all sources are colored and skewed to some extent, there is no way to uncover an ‘absolute truth’. In fact, an absolute truth, in itself, is non-existent. Epistemology is important because it contours how we think. Modern epistemology is a conjunction of two fundamental theories - empiricism and rationalism, and how the clash between the two gives rise to various theories and questions.

Empiricism is a theory that knowledge is acquired from the senses. Advocated by philosophers such as John Locke, David Hume, and George Berkeley, it was enthused by the advent of experimental science and developed through the seventeenth and eighteenth centuries. On the other hand, rationalism is the theory that knowledge is obtained by the application of reason. Reason is here given a higher priority than experience and is promoted as the basic foundation in deciding the certainty of knowledge. Classical rationalists include Rene Descartes, Immanuel Kant, and Gottfried Leibniz. I found both schools equally intriguing, but incomplete in some regard, even though they form a mutually exhaustive set of ways to obtain knowledge.

The first two philosophers that come to mind are John Locke and Bishop Berkeley. Locke, a seventeenth century British empiricist, thought of his philosophy as being adjunct to Newtonian physics and argued the presence of two kinds of qualities, primary and secondary. Primary qualities are physical qualities, such as hardness, mass or wavelength, and relate to the physical concepts of quantification. Secondary qualities, on the other hand, are subjective and obtained through immediate sensory inputs, such as taste, smell or texture. Berkeley was an eighteenth century Anglo-Irish empiricist who believed that being was equivalent to perceiving. Critical of Newton, he argued that only secondary qualities exist, since they are the only ones that are perceivable. Grounded in Christianity, he hailed God as the constant perceiver, hence justifying the existence of an object even when not in sight of a human. Although on the outside, his philosophy sounded quite convincing to me, I found it hard to agree on the premise that secondary qualities do not exist at all. Little did I know that we were yet to be introduced to another radical philosopher, David Hume.

Hume was yet another empiricist, with a visibly different flavor in his arguments. An eighteenth century Scottish philosopher, he urged that knowledge comes from sensory experiences, and all the perceptions of the human mind could be safely classified into either impressions or ideas. Ideas emerge from impressions, and impressions put the existence of matter to a question mark. He went on to give the induction and causation theory, saying that there is no such thing as a cause-and-effect pair, only correlations of events in the universe. So, saying that fire caused the burn is improvable; only that there is a correlation between fire and the burns. He also propelled the bundle theory of personal identity and shared Buddha’s idea of “no self” with subtle differences.

As opposed to empiricists, rationalists debated that knowledge comes from mind structures and rational principles. The most important rationalist discussed in class is René Descartes, a seventeenth century French philosopher who gave the famous philosophical statement “Cogito ergo sum” meaning “I think, therefore I am”. According to him, the solid foundation for the principles of reason is the thinking self. I do not buy the complete empiricist idea, owing to the fact that perceptions and sensations differ among cultures, groups, and even individuals. Also, how would one justify the existence of the color blue, to say, someone who was born blind? Hence, there are certain things that exist beyond perception. We are blind to myriad other colors and wavelengths that cannot be sensed by the human eye. However, this does not negate their existence. Again, rationalism cannot account for all the things that exist, since every knowledge cannot be obtained through a priori (prior to experience), and not all can be traced back to the roots of logic and reason in the human mind. Empiricism is easier, as rationalism incorporates the innate knowledge or reasoning as a separate independent entity existing outside of the five senses. However, rationalism extends humans to something more than what they simply experience, which sounds very convincing, as had we been all about our senses, we would have been very easily manageable by external forces. Science could not have advanced without a subtle intermingling of both, as it integrates both empirical knowledge as well as building upon the observation through delicate reasoning and logic.