Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
a posteriori, a priori
To reason a posteriori means to reason “from effect back to cause, from particulars to generalizations, inductively, empirically.” To reason a priori is exactly the opposite process: to reason “from cause forward to effect, from generalizations to particulars, deductively.” A priori reasoning is theoretical, based on logic; a posteriori reasoning is practical, based on experience and experimentation.
