Epistemology

Epistemology is the branch of philosophy that examines the nature, origin, and limits of knowledge. Also called the theory of knowledge, it explores different types of knowledge, such as propositional knowledge about facts, practical knowledge in the form of skills, and knowledge by acquaintance as a familiarity through experience. Epistemologists study the concepts of belief, truth, and justification to understand the nature of knowledge. To discover how knowledge arises, they investigate sources of justification, such as perception, introspection, memory, reason, and testimony.

The school of skepticism questions the human ability to attain knowledge, while fallibilism says that knowledge is never certain. Empiricists hold that all knowledge comes from sense experience, whereas rationalists believe that some knowledge does not depend on it. Coherentists argue that a belief is justified if it coheres with other beliefs. Foundationalists, by contrast, maintain that the justification of basic beliefs does not depend on other beliefs. Internalism and externalism debate whether justification is determined solely by mental states or also by external circumstances.

Separate branches of epistemology focus on knowledge in specific fields, like scientific, mathematical, moral, and religious knowledge. Naturalized epistemology relies on empirical methods and discoveries, whereas formal epistemology uses formal tools from logic. Social epistemology investigates the communal aspect of knowledge, and historical epistemology examines its historical conditions. Epistemology is closely related to psychology, which describes the beliefs people hold, while epistemology studies the norms governing the evaluation of beliefs. It also intersects with fields such as decision theory, education, and anthropology.

Early reflections on the nature, sources, and scope of knowledge are found in ancient Greek, Indian, and Chinese philosophy. The relation between reason and faith was a central topic in the medieval period. The modern era was characterized by the contrasting perspectives of empiricism and rationalism. Epistemologists in the 20th century examined the components, structure, and value of knowledge while integrating insights from the natural sciences and linguistics.

Epistemology is the philosophical study of knowledge and related concepts, such as justification. Also called theory of knowledge, it examines the nature and types of knowledge. It further investigates the sources of knowledge, like perception, inference, and testimony, to understand how knowledge is created. Another set of questions concerns the extent and limits of knowledge, addressing what people can and cannot know. Central concepts in epistemology include belief, truth, evidence, and reason. As one of the main branches of philosophy, epistemology stands alongside fields like ethics, logic, and metaphysics. The term can also refer specific positions of philosophers within this branch, as in Plato's epistemology and Immanuel Kant's epistemology.

Epistemology explores how people should acquire beliefs. It determines which beliefs or forms of belief acquisition meet the standards or epistemic goals of knowledge and which ones fail, thereby providing an evaluation of beliefs. The fields of psychology and cognitive sociology are also interested in beliefs and related cognitive processes, but examine them from a different perspective. Unlike epistemology, they study the beliefs people actually have and how people acquire them instead of examining the evaluative norms of these processes. In this regard, epistemology is a normative discipline, whereas psychology and cognitive sociology are descriptive disciplines. Epistemology is relevant to many descriptive and normative disciplines, such as the other branches of philosophy and the sciences, by exploring the principles of how they may arrive at knowledge.

The word epistemology comes from the ancient Greek terms ἐπιστήμη (episteme, meaning knowledge or understanding) and λόγος (logos, meaning study of or reason), literally, the study of knowledge. Despite its ancient roots, the word itself was coined only in the 19th century to designate this field as a distinct branch of philosophy.

Epistemologists examine several foundational concepts to understand their essences and rely on them to formulate theories. Various epistemological disagreements have their roots in disputes about the nature and function of these concepts, like the controversies surrounding the definition of knowledge and the role of justification in it.