Epistemology is the branch of philosophy concerned with knowledge. Epistemologists study the nature, origin, and scope of knowledge, epistemic justification, the rationality of belief, and various related issues. Debates in (contemporary) epistemology are generally clustered around four core areas:
- The philosophical analysis of the nature of knowledge and the conditions required for a belief to constitute knowledge, such as truth and justification
- Potential sources of knowledge and justified belief, such as perception, reason, memory, and testimony
- The structure of a body of knowledge or justified belief, including whether all justified beliefs must be derived from justified foundational beliefs or whether justification requires only a coherent set of beliefs
- Philosophical skepticism, which questions the possibility of knowledge, and related problems, such as whether skepticism poses a threat to our ordinary knowledge claims and whether it is possible to refute skeptical arguments
Foundationalism concerns philosophical theories of knowledge resting upon non-inferential justified belief, or some secure foundation of certainty such as a conclusion inferred from a basis of sound premises. The main rival of the foundationalist theory of justification is the coherence theory of justification, whereby a body of knowledge, not requiring a secure foundation, can be established by the interlocking strength of its components, like a puzzle solved without prior certainty that each small region was solved correctly.
Reliabilism, a category of theories in the philosophical discipline of epistemology, has been advanced as a theory both of justification and of knowledge. Process reliabilism has been used as an argument against philosophical skepticism, such as the brain in a vat thought experiment. Process reliabilism is a form of epistemic externalism.
In epistemology, the regress argument is the argument that any proposition requires a justification. However, any justification itself requires support. This means that any proposition whatsoever can be endlessly (infinitely) questioned, resulting in infinite regress. It is a problem in epistemology and in any general situation where a statement has to be justified.
Knowledge is an awareness of facts, a familiarity with individuals and situations, or a practical skill. Knowledge of facts, also called propositional knowledge, is often characterized as true belief that is distinct from opinion or guesswork by virtue of justification. While there is wide agreement among philosophers that propositional knowledge is a form of true belief, many controversies focus on justification. This includes questions like how to understand justification, whether it is needed at all, and whether something else besides it is needed. These controversies intensified due to a series of thought experiments by Edmund Gettier and have provoked various alternative definitions.
The Gettier problem, in the field of epistemology, is a landmark philosophical problem concerning the understanding of descriptive knowledge. Attributed to American philosopher Edmund Gettier, Gettier-type counterexamples challenge the long-held justified true belief (JTB) account of knowledge. The JTB account holds that knowledge is equivalent to justified true belief; if all three conditions are met of a given claim, then we have knowledge of that claim. In his 1963 three-page paper titled "Is Justified True Belief Knowledge?", Gettier attempts to illustrate by means of two counterexamples that there are cases where individuals can have a justified, true belief regarding a claim but still fail to know it because the reasons for the belief, while justified, turn out to be false. Thus, Gettier claims to have shown that the JTB account is inadequate because it does not account for all of the necessary and sufficient conditions for knowledge.
In philosophical epistemology, there are two types of coherentism: the coherence theory of truth; and the coherence theory of justification.
Empirical evidence for a proposition is evidence, i.e. what supports or counters this proposition, that is constituted by or accessible to sense experience or experimental procedure. Empirical evidence is of central importance to the sciences and plays a role in various other fields, like epistemology and law.
Evidentialism is a thesis in epistemology which states that one is justified to believe something if and only if that person has evidence which supports said belief. Evidentialism is, therefore, a thesis about which beliefs are justified and which are not.
Virtue epistemology is a current philosophical approach to epistemology that stresses the importance of intellectual and specifically epistemic virtues. Virtue epistemology evaluates knowledge according to the properties of the persons who hold beliefs in addition to or instead of the properties of the propositions and beliefs. Some advocates of virtue epistemology also adhere to theories of virtue ethics, while others see only loose analogy between virtue in ethics and virtue in epistemology.
In the philosophy of religion, Reformed epistemology is a school of philosophical thought concerning the nature of knowledge (epistemology) as it applies to religious beliefs. The central proposition of Reformed epistemology is that beliefs can be justified by more than evidence alone, contrary to the positions of evidentialism, which argues that while non-evidential belief may be beneficial, it violates some epistemic duty. Central to Reformed epistemology is the proposition that belief in God may be "properly basic" and not need to be inferred from other truths to be rationally warranted. William Lane Craig describes Reformed epistemology as "One of the most significant developments in contemporary religious epistemology ... which directly assaults the evidentialist construal of rationality."
Naturalized epistemology is a collection of philosophic views concerned with the theory of knowledge that emphasize the role of natural scientific methods. This shared emphasis on scientific methods of studying knowledge shifts focus to the empirical processes of knowledge acquisition and away from many traditional philosophical questions. There are noteworthy distinctions within naturalized epistemology. Replacement naturalism maintains that traditional epistemology should be abandoned and replaced with the methodologies of the natural sciences. The general thesis of cooperative naturalism is that traditional epistemology can benefit in its inquiry by using the knowledge we have gained from the cognitive sciences. Substantive naturalism focuses on an asserted equality of facts of knowledge and natural facts.
Laurence BonJour is an American philosopher and Emeritus of Philosophy at the University of Washington.
Metaepistemology is the branch of epistemology and metaphilosophy that studies the underlying assumptions made in debates in epistemology, including those concerning the existence and authority of epistemic facts and reasons, the nature and aim of epistemology, and the methodology of epistemology.
Infallibilism is the epistemological view that propositional knowledge is incompatible with the possibility of being wrong.
Infinitism is the view that knowledge may be justified by an infinite chain of reasons. It belongs to epistemology, the branch of philosophy that considers the possibility, nature, and means of knowledge.
The following outline is provided as an overview of and topical guide to epistemology:
Epistemology or theory of knowledge is the branch of philosophy concerned with the nature and scope (limitations) of knowledge. It addresses the questions "What is knowledge?", "How is knowledge acquired?", "What do people know?", "How do we know what we know?", and "Why do we know what we know?". Much of the debate in this field has focused on analyzing the nature of knowledge and how it relates to similar notions such as truth, belief, and justification. It also deals with the means of production of knowledge, as well as skepticism about different knowledge claims.
Jennifer Lackey is an American academic; she is the Wayne and Elizabeth Jones Professor of Philosophy at Northwestern University. Lackey is known for her research in epistemology, especially on testimony, disagreement, memory, the norms of assertion, and virtue epistemology. She is the author of Learning from Words: Testimony as a Source of Knowledge and of numerous articles and book chapters. She is also co-editor of The Epistemology of Testimony and The Epistemology of Disagreement: New Essays.
Definitions of knowledge try to determine the essential features of knowledge. Closely related terms are conception of knowledge, theory of knowledge, and analysis of knowledge. Some general features of knowledge are widely accepted among philosophers, for example, that it constitutes a cognitive success or an epistemic contact with reality and that propositional knowledge involves true belief. Most definitions of knowledge in analytic philosophy focus on propositional knowledge or knowledge-that, as in knowing that Dave is at home, in contrast to knowledge-how (know-how) expressing practical competence. However, despite the intense study of knowledge in epistemology, the disagreements about its precise nature are still both numerous and deep. Some of those disagreements arise from the fact that different theorists have different goals in mind: some try to provide a practically useful definition by delineating its most salient feature or features, while others aim at a theoretically precise definition of its necessary and sufficient conditions. Further disputes are caused by methodological differences: some theorists start from abstract and general intuitions or hypotheses, others from concrete and specific cases, and still others from linguistic usage. Additional disagreements arise concerning the standards of knowledge: whether knowledge is something rare that demands very high standards, like infallibility, or whether it is something common that requires only the possession of some evidence.
