Greek episteme (knowledge) +
logeo (to speak). The theory of knowledge: the study of the nature, sources, and validity of knowledge. It differs from logic and
psychology . Logic is concerned with the specific and formal problem of correct reasoning, while epistemology deals with the nature of reasoning, with truth, and with the process of knowing themselves.
Psychology is concerned with a descriptive study of behavior,
phenomena , etc., while epistemology deals with our claims to knowledge, i.e., what we mean by "knowing." See
Epistemological realism and
knowledge