Epistemology or theory of knowledge is the branch of philosophy that studies the nature, methods, limitations, and validity of knowledge and belief.
The term "epistemology" is based on the Greek words "επιστήμη or episteme" (knowledge or science) and "λόγος or logos" (account/explanation). It was introduced into English by the Scottish philosopher James Frederick Ferrier (1808-1864).
Much of the debate in this field has focused on analyzing the nature of knowledge and how it relates to similar notions such as truth, belief, and justification. It also deals with the means of production of knowledge, as well as skepticism about different knowledge claims. In other words, epistemology primarily addresses the following questions: "What is knowledge?", "How is knowledge acquired?", and "What do people know?".