a priori knowledge
Before-experience insight
Knowledge that can be gained independently of experience, through reason or logic alone.
Mathematical truths and logical deductions are classic examples: you don't need to observe the world to know that 2 + 2 = 4 or that all bachelors are unmarried.
Contrasts with *a posteriori* knowledge, which requires empirical observation.
We know a priori that a triangle has three sides.
- reasoningDrawing logical conclusions
- PlatonismPhilosophy emphasizing ideal Forms
- mathematicsScience of quantity and structure
- deductionConclusion from premises
- formal logicRule-governed deductive system
axioms · intuition · rationalism · necessity · first principles · geometry · foundationalism · propositions · armchair philosophy · tautologies · universality · idealism · metaphysics · self-evidence · self-evident truths · Kant · synthetic a priori · validity
- knowledgeknowledge, common knowledge, general knowledge, factual knowledge, prior knowledge
- philosophyethics, logic, metaphysics, ontology, epistemology
- epistemologyknowledge, belief, justification, truth, certainty
- KantKant, categorical imperative, a priori, thing-in-itself, noumena
- Kantian PhilosophyKant, categorical imperative, a priori, noumena, phenomena
- RationalismDescartes, cogito ergo sum, a priori, Spinoza, clear ideas