Wiktionary
epistemological turn
n. (context philosophy English) 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 http://en.wikipedia.org/wiki/Ren%C3%A9_Descartes (1596-1650) through http://en.wikipedia.org/wiki/Immanuel_Kant (1724-1804).