a priori
ay pry-OR-ey
/ˌeɪ praɪˈɔːraɪ/
Relating to or denoting reasoning or knowledge that proceeds from theoretical deduction rather than from observation or experience.
Refers to truths known through pure reason alone, such as mathematical facts or logical tautologies.
The story behind the word. Scholastic philosophers in the Middle Ages coined this Latin phrase to distinguish arguments that move from causes to effects ('from what comes before') from arguments that move from effects back to causes ('a posteriori'). Immanuel Kant famously popularized the term in epistemology.
Word relationships
- deductive: Refers to the process of deriving specific conclusions from general premises.
- theoretical: Broader term that includes models that may eventually require empirical verification.
- a posteriori: Denotes knowledge derived solely from experience or empirical evidence.
- empirical: Relies strictly on sensory observation rather than independent reason.
Commonly confused with
- empirical: A priori relies on logic before experience; empirical relies on observation after experience.
Collocations
- a priori knowledge
- a priori reasoning
- a priori assumption
- a priori truth
Example sentences
- "That all triangles have three sides is an a priori truth that requires no empirical survey to confirm." Mathematics
- "The judge rejected the defense argument because it relied on an unsupported a priori assumption." Legal Reasoning
Memory hook
A PRIORI = PRIOR to looking around the world, you already know it by pure logic. Prior to experience—known by pure mind.
When not to use
Do not use to describe physical facts that require real-world measurement or investigation.
Fun facts
- Kant argued that space and time are a priori forms of human perception.
Related words
Also appears in
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