Plain-language explanation.
Epistemology is the branch of philosophy concerned with the nature, sources, and limits of knowledge. It asks: what is knowledge? How do we come to know things? Can we be certain of anything? It underpins every discipline that makes knowledge claims.
Core concepts and standard treatment.
Classic epistemology distinguishes propositional knowledge (knowledge-that), procedural knowledge (knowledge-how), and acquaintance knowledge. The tripartite definition (justified true belief — JTB) was disrupted by Gettier cases. Foundationalism, coherentism, and reliabilism offer competing accounts of how beliefs are justified.
Deeper theory, debates and edge cases.
Advanced epistemology covers social epistemology (Fricker — epistemic injustice, testimonial injustice), naturalised epistemology (Quine), virtue epistemology (intellectual humility, open-mindedness as epistemic virtues), Bayesian epistemology (probabilistic belief revision), and feminist standpoint theory's challenge to value-neutral objectivity.
How it is applied in practice.
At the research and policy adviser level, epistemologists contribute to debates on scientific consensus and public reasoning, advise on evidence standards in law and policy (epistemic peer disagreement), publish in journals including Episteme and Synthese, and apply epistemological frameworks to AI knowledge representation and the design of reliable automated reasoning systems.