“The Latin phrases a priori (lit. “from the earlier”) and a posteriori (lit. “from the latter”) are philosophical terms of art popularised by Immanuel Kant’s Critique of Pure Reason (first published in 1781, second edition in 1787), one of the most influential works in the history of philosophy. However, in their Latin forms they appear in Latin translations of Euclid’s Elements, of about 300 bce, a work widely considered during the early European modern period as the model for precise thinking.
These terms are used with respect to reasoning (epistemology) to distinguish “necessary conclusions from first premises” (i.e., what must come before sense observation) from “conclusions based on sense observation” (which must follow it). Thus, the two kinds of knowledge, justification, or argument may be glossed:
- A priori knowledge or justification is independent of experience, as with mathematics (3 000 + 2 000 = 5 000), tautologies (“All bachelors are unmarried”), and deduction from pure reason (e.g., ontological proofs).
- A posteriori knowledge or justification is dependent on experience or empirical evidence, as with most aspects of science and personal knowledge.
There are many points of view on these two types of knowledge, and their relationship gives rise to one of the oldest problems in modern philosophy.
The terms a priori and a posteriori are primarily used as adjectives to modify the noun “knowledge” (for example, “a priori knowledge”). However, “a priori” is sometimes used to modify other nouns, such as “truth”. Philosophers also may use “apriority” and “aprioricity” as nouns to refer (approximately) to the quality of being “a priori“.[not in citation given]
Although definitions and use of the terms have varied in the history of philosophy, they have consistently labeled two separate epistemological notions. See also the related distinctions: deductive/inductive, analytic/synthetic, necessary/contingent.’
Offering opinion pieces and academic perspectives on both UK and global current events, The Priori is a free and online-exclusive magazine. New issues are released on the first day of every month.
The Priori was founded in August 2015, and released the first of its monthly issues in November 2015.
The Priori was registered in November 2016 as a part of Priori Media Group.