Gettier problemThe 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 (called "Gettier-cases") 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 (justification, truth, and belief) are met of a given claim, then we have knowledge of that claim.
Declarative knowledgeDeclarative knowledge is an awareness of facts that can be expressed using declarative sentences, like knowing that Princess Diana died in 1997. It is also called theoretical knowledge, descriptive knowledge, propositional knowledge, and knowledge-that. It is not restricted to one specific use or purpose and can be stored in books or on computers. Epistemology is the main discipline studying declarative knowledge. Among other things, it studies the essential components of declarative knowledge.
Dream argumentThe dream argument is the postulation that the act of dreaming provides preliminary evidence that the senses we trust to distinguish reality from illusion should not be fully trusted, and therefore, any state that is dependent on our senses should at the very least be carefully examined and rigorously tested to determine whether it is in fact reality. While dreaming, one does not normally realize one is dreaming. On more rare occasions, the dream may be contained inside another dream with the very act of realizing that one is dreaming, itself, being only a dream that one is not aware of having.
Procedural knowledgeProcedural knowledge (also known as knowing-how, and sometimes referred to as practical knowledge, imperative knowledge, or performative knowledge) is the knowledge exercised in the performance of some task. Unlike descriptive knowledge (also known as declarative knowledge, propositional knowledge or "knowing-that"), which involves knowledge of specific facts or propositions (e.g. "I know that snow is white"), procedural knowledge involves one's ability to do something (e.g. "I know how to change a flat tire").
EvidentialismEvidentialism 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. For philosophers Richard Feldman and Earl Conee, evidentialism is the strongest argument for justification because it identifies the primary notion of epistemic justification. They argue that if a person's attitude towards a proposition fits their evidence, then their doxastic attitude for that proposition is epistemically justified.
EpistemeIn philosophy, episteme (epistēmē; épistémè) is knowledge or understanding. The term epistemology (the branch of philosophy concerning knowledge) is derived from episteme. Plato, following Xenophanes, contrasts episteme with doxa: common belief or opinion. The term episteme is also distinguished from techne: a craft or applied practice. In the Protagoras, Plato's Socrates notes that nous and episteme are prerequisites for prudence (phronesis).
Knowledge by acquaintanceIn philosophy, a distinction is often made between two different kinds of knowledge: knowledge by acquaintance and knowledge by description. Whereas knowledge by description is something like ordinary propositional knowledge (e.g. "I know that snow is white"), knowledge by acquaintance is familiarity with a person, place, or thing, typically obtained through perceptual experience (e.g. "I know Sam", "I know the city of Bogotá", or "I know Russell's Problems of Philosophy").
Virtue epistemologyVirtue 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.
Propositional attitudeA propositional attitude is a mental state held by an agent or organism toward a proposition. In philosophy, propositional attitudes can be considered to be, neurally-realized causally efficacious content-bearing internal states (personal principles/values). Linguistically, propositional attitudes are denoted by a verb (e.g. "believed") governing an embedded "that" clause, for example, 'Sally believed that she had won'. Propositional attitudes are often assumed to be the fundamental units of thought and their contents, being propositions, are true or false from the perspective of the person.
InfinitismInfinitism 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. Since Gettier, "knowledge" is no longer widely accepted as meaning "justified true belief" only. However, some epistemologists still consider knowledge to have a justification condition. Traditional theories of justification (foundationalism and coherentism) and indeed some philosophers consider an infinite regress not to be a valid justification.
