The Greeks were one of the most influential cultures in the history of philosophy. Their contributions to the field of epistemology, the study of knowledge, have had a lasting impact on Western thought. In general, the epistemology of the Greeks can be divided into two main schools: rationalism and empiricism.


Rationalism is the belief that knowledge can be obtained through reason alone, without relying on sensory experience. This school of thought was first championed by the ancient philosopher Plato.

According to Plato, knowledge is not something that can be obtained through our senses but rather something that exists independently of them. He believed that there are eternal Forms or Ideas that exist in a higher realm and that our senses can only give us imperfect copies of these Forms.

Example: For instance, a chair we perceive through our senses is just a copy or an imitation of the true Form or Idea of a chair which exists independently in a higher realm.

Plato’s student Aristotle also believed in rationalism but he focused more on observation and logic than on pure reason. Aristotle believed that knowledge comes from observation and experience but only if it is guided by reason and logic. He saw reason as the key to unlocking knowledge and understanding.


Empiricism is another school of thought in epistemology which holds that knowledge comes from sensory experience. This school was first championed by the ancient philosopher Aristotle’s younger contemporary, Epicurus. Epicurus believed that all knowledge comes from sensory experiences and observations.

Example: For instance, if we want to know how hot water is, we have to touch it or feel it with our skin. We cannot know how hot it is just by thinking about it.

Another prominent empiricist was Sextus Empiricus who believed that there was no way to truly know anything for sure. He argued that all knowledge and beliefs are based on perception and therefore, they are always subject to doubt.


In conclusion, the Greeks made significant contributions to the field of epistemology with their schools of thought, rationalism and empiricism. While rationalism emphasizes reason as the source of knowledge, empiricism emphasizes sensory experience. Both schools have had a lasting impact on Western philosophy and continue to shape our understanding of knowledge today.