The Scottish philosopher James Frederick Ferrier was the first person to use the term epistemology to describe the branch of philosophy that studies the nature and scope of knowledge. It is also known as the “theory of knowledge,” and in a nutshell, it is the study of what it means to know something and to have a good reason to believe it.

It asks what knowledge is and how it can be gained, as well as how much knowledge can be gained about any given subject or thing. A lot of the debate in this field has been about the philosophical analysis of what knowledge is and how it relates to related ideas like truth, belief, and justification.

The term was presumably first used in Ferrier’s Institutes of Metaphysics: The Theory of Knowing and Being (1854), page 46.