Epistemology is the branch of philosophy that deals with the study of knowledge. It seeks to answer fundamental questions about what knowledge is, how it is acquired, and what makes it possible. In this article, we will explore how epistemology defines knowledge.

What is Knowledge?

Knowledge can be defined as justified true belief. In other words, for something to count as knowledge, it must meet three criteria: it must be true, we must believe it to be true, and our belief must be justified.

Theories of Knowledge

There are many different theories of knowledge in epistemology. Let’s take a look at a few:

The Gettier Problem

In 1963, philosopher Edmund Gettier published a paper called “Is Justified True Belief Knowledge?” In it, he presented a problem for the traditional definition of knowledge.

Gettier argued that there could be cases where someone has a justified true belief but does not have knowledge. For example, imagine you see a clock on a wall that reads 2:00 pm and you believe it is 2:00 pm.

Unbeknownst to you, the clock stopped working at 2:00 pm the previous day, so your belief is true because of a lucky coincidence and not because of any real justification. Gettier argued that this belief does not count as knowledge.


Epistemology is a fascinating field that deals with some of the most fundamental questions about knowledge. While there are many different theories of knowledge, they all share the common thread that for something to count as knowledge, it must be justified true belief. The Gettier problem has challenged this definition, but philosophers continue to debate and refine their ideas about what it means to have knowledge.