a priori and a posteriori
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a priori and a posteriori(literally ‘what comes before’ and ‘what comes after’) a distinction made between kinds of statements or propositions according to the manner in which we acquire knowledge of their truth; thus, whereas an a priori statement is one that can be known to be true or false without reference to experience or empirical evidence (e.g. the definition of a square as having four equal sides), the truth of an a posteriori statement can be established only by an examination of what is empirically the case. While many ‘rationalist’ philosophers, most notably in modern times KANT, have argued that some things can, and indeed must, be known a priori, merely from first principles, the opposing view – philosophical EMPIRICISM – holds that our ideas are derived only from ‘experience’ (see also HUME). More recently the view has been expressed that neither of these positions are satisfactory, that there is no fixed starting point or ultimate grounding in philosophy or knowledge. Compare ANALYTIC AND SYNTHETIC.
Collins Dictionary of Sociology, 3rd ed. © HarperCollins Publishers 2000