I was a philosophy student and am now an academic philosopher and lawyer. From time to time I incorporate various philosophical notions into my game, in various ways.
The attached document is something that I wrote up for my campaign when I was an undergraduate, and thus had more time for such things (and hadn't moved as far as I now have from an exploratory style of play). It is for a Greyhawk game, but incorporates other elements from Dragonlance, AD&D's Deities and Demigods, plus some of my own material. It incorporates the history of European epistemology (and some associated metaphysical issues) - as understood by me at the time - into the religious orders of the gameworld.