Epistemology

The unexamined life is not worth living.
Socrates, in Plato, Dialogues, Apology

Epistemology (from Greek ???????? - episteme-, "knowledge, science" + ?????, "logos") or theory of knowledge is the branch of philosophy concerned with the nature, structure, and scope (limitations) of knowledge.
It addresses the questions:
What is knowledge?
How is knowledge acquired?
What do people know?
How do we know what we know?

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.

The term was introduced into English by the Scottish philosopher James Frederick Ferrier (1808–1864)