A priori and a posteriori

A priori knowledge is justified independently of experience, while a posteriori knowledge depends on experience. The distinction concerns how knowledge is justified, not whether it is certain or universal.

Epistemology: The branch of philosophy that studies knowledge, justification, and belief. This distinction classifies sources of justification, a central epistemological question.
Empiricism: The view that experience is the primary source or test of knowledge. Empiricism challenges claims that substantive knowledge can arise independently of experience.
Mathematical knowledge: Knowledge of mathematical truths, proofs, and structures. Its apparent independence from observation makes it a central test case for a priori knowledge.
Immanuel Kant: An eighteenth-century German philosopher who argued that the mind actively structures experience. Kant made synthetic a priori judgment central to his account of knowledge.
Justification: The support that makes a belief epistemically reasonable or warranted. The distinction concerns whether justification depends on experience.
Rationalism: The view that reason can provide knowledge beyond what sensory experience supplies. Rationalism gives a priori knowledge a larger role than empiricism typically allows.
Moral epistemology: The study of how moral beliefs can be justified and known. Debates ask whether moral truths are known by reason or grounded in experience.
David Hume: A Scottish philosopher known for his empiricist account of knowledge and skepticism about causation. Hume distinguished relations of ideas from matters of fact, shaping later debates about the distinction.
Empirical evidence: Information gathered through observation, measurement, or experiment. Such evidence grounds a posteriori claims.
Kantian synthetic a priori: Kant’s category of judgments that extend knowledge yet are knowable independently of particular experiences. Kant used this category to challenge the assumption that a priori truths are merely analytic.

Linked from 12 pages