epistemological turn

noun1

1. •
   In the history of Western philosophy, the shift in philosophical attention from the classical and medieval focus on themes of metaphysics to a primary focus on themes and issues relating to human knowledge, usually considered to have occurred during the period from Descartes (1596-1650) through Kant (1724-1804).

   • The core of Kant's "epistemological turn" is the claim that the distinction between epistemic and ontological categories is an illusion. — 1967