Epistemology

Epistemology is also called Theory of Knowledge. A philosophical discipline, it deals with broad questions: what is knowledge? Is certainty required for knowledge, and what is certainty anyway? From what sources--sense-perception, say, or revelation--do we derive knowledge? Our beliefs can have more or less justification, warrant, or evidence--and these features seem, roughly speaking, required for knowledge. So what are they? Some doubt that we have any, or very much, knowledge at all. On what grounds can we embrace, or reject, such skepticism?