Abstract
Rejection of the philosophical relevance of history of philosophy remains pronounced within contemporary analytic philosophy. The two main reasons for this rejection presuppose that strict deduction is both necessary and sufficient for rational justification. However, this justificatory ideal of scientia holds only within strictly formal domains. This is confirmed by a neglected non-sequitur in van Fraassen’s original defence of ‘Constructive Empiricism’. Conversely, strict deduction is insufficient for rational justification in non-formal, substantive domains of inquiry. In non-formal, substantive domains, rational justification is also, in part, ineliminably social and historical, for sound reasons Hegel was the first to articulate. Demonstrating this involves considering closely two key reasons many analytic philosophers (still) reject the philosophical relevance of historical philosophy (§2). As specific example of presumed, though fallacious, deductivism about justification in the non-formal domain of empirical knowledge is found in van Fraassen’s (1980) defence of ‘Constructive Empiricism’ (§3). These first two sections contend that philosophical consideration of historical philosophy is required to properly formulate key issues in non-formal domains. I next consider the further issues involved rational justification in non-formal domains, issues quintessentially posed by the Pyrrhonian Dilemma of the Criterion (§4). Finally I consider what kind of history of philosophy is required for cogent philosophy in non-formal domains (§5).