A priori and a posteriori

Two types of knowledge, justification, or argument

In epistemology, a priori (‘from the earlier’) and a posteriori (‘from the later’) are the two categories of knowledge, justification, or argument, determining whether or not a proposition is reliant on outside sensory experience. Roughly speaking, a proposition is known or justified a priori if it is known or justified independently of any experience (beyond the experience necessary to understand the proposition). It is known or justified a posteriori if its knowledge and/or justification depends on empirical evidence.

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