Epistemology (/ɪˌpɪstɪˈmɒlədʒi/ ( listen); from Greek, Modern ἐπιστήμη, epistēmē, meaning ‘knowledge’, and λόγος, logos, meaning ‘logical discourse’) is the branch of philosophy concerned with the theory of knowledge.^[1]

Epistemology is the study of the nature of knowledge, justification, and the rationality of belief. Much debate in epistemology centers on four areas: (1) the philosophical analysis of the nature of knowledge and how it relates to such concepts as truth, belief, and justification,^[2][3] (2) various problems of skepticism, (3) the sources and scope of knowledge and justified belief, and (4) the criteria for knowledge and justification. Epistemology addresses such questions as: “What makes justified beliefs justified?”,^[4] “What does it mean to say that we know something?”,^[5] and fundamentally “How do we know that we know?”.^[6]