|1.||(Logic) Characterizing that kind of reasoning which deduces consequences from definitions formed, or principles assumed, or which infers effects from causes previously known; deductive or deductively. The reverse of a posteriori.|
|3.||(Philos.) Applied to knowledge and conceptions assumed, or presupposed, as prior to experience, in order to make experience rational or possible.|
|Adj.||1.||a priori - involving deductive reasoning from a general principle to a necessary effect; not supported by fact; "an a priori judgment"|
a posteriori - involving reasoning from facts or particulars to general principals or from effects to causes; "a posteriori demonstration"
|2.||a priori - based on hypothesis or theory rather than experiment|
|Adv.||1.||a priori - derived by logic, without observed facts|
a posteriori - derived from observed facts