a priori
Known through reason
A priori describes knowledge or reasoning that proceeds from theoretical principles rather than from observation or experience.
In philosophy, a priori truths can be known through reason alone: We know a priori that all bachelors are unmarried.
The term contrasts with a posteriori, which depends on empirical evidence.
Outside philosophy, a priori often means presumed in advance or based on assumption rather than investigation: He dismissed the idea a priori, without examining the evidence.
Theory of knowledge
- rationalismReason as knowledge source
- KantGerman Enlightenment thinker
- transcendentalBeyond ordinary experience
- synthetic a prioriNecessary truths that expand knowledge
analytic · categories · pure reason · metaphysics · Descartes · Leibniz · Hume · idealism
Conclusion from premises
- axiomSelf-evident starting principle
- tautologyRedundant or circular statement
- syllogismFormal deductive argument structure
- theoremDemonstrated logical conclusion
proof · validity · necessity · inference · premise · conclusion · proposition · formal logic
Unverified belief accepted as true
- givenAccepted as fact
- presuppositionImplicit prior assumption
- prerequisiteRequired prior condition
- preconditionNecessary prior requirement
foundational · underlying · implicit · baseline · starting point · framework · postulate · stipulation
Existing from birth
- inherentExisting as essential part
- intrinsicBelonging by nature
- intuitiveKnown without reasoning
- hardwiredPermanently connected by wires
instinctive · native · unlearned · natural · intuition · constitutional · essential · primordial
Impossible to doubt
- necessaryIndispensable, cannot omit
- universalAffecting all equally
- absoluteTotal, without qualification
- unquestionableCannot be challenged
incontrovertible · self-evident · undeniable · irrefutable · axiomatic · certain · infallible
epistemology
Theory of knowledge
- rationalismReason as knowledge source
- KantGerman Enlightenment thinker
- transcendentalBeyond ordinary experience
synthetic a priori · analytic · categories · pure reason · metaphysics · Descartes · Leibniz · Hume · idealism · Platonic
deduction
Conclusion from premises
- axiomSelf-evident starting principle
- tautologyRedundant or circular statement
- syllogismFormal deductive argument structure
theorem · proof · validity · necessity · inference · premise · conclusion · proposition · formal logic · corollary
assumption
Unverified belief accepted as true
- givenAccepted as fact
- presuppositionImplicit prior assumption
- prerequisiteRequired prior condition
precondition · foundational · underlying · implicit · baseline · starting point · framework · postulate · stipulation · groundwork
inborn
Existing from birth
hardwired · instinctive · native · unlearned · natural · intuition · constitutional · essential · primordial
indubitable
Impossible to doubt
- necessaryIndispensable, cannot omit
- universalAffecting all equally
- absoluteTotal, without qualification
unquestionable · incontrovertible · self-evident · undeniable · irrefutable · axiomatic · certain · infallible
- Latin Termsab initio, ad hoc, ad lib, bona fide, circa
- metaphysicsessence, being, reality, existence, substance theory
- philosophyethics, logic, metaphysics, ontology, epistemology
- philosophy termstruth, reason, knowledge, wisdom, logic
- logic termsif, then, valid, premises, and
- philosophical termsSocratic, Kantian, Cartesian, Aristotelian, dialectical
a prioriempirical
Based on observation, not theory
experiential · observational · data-driven · inductive · evidence-based
a prioriafter the fact
Following an event's occurrence
post hoc · retrospective · in hindsight · ex post facto · evidence-based
priority, prioritize, priorities, prioritized, prioritizing, prioritization