The Foundation Doctrines
Descartes's famous proclamation, "Cogito, ergo sum"—"I think, therefore I am"—was borne of a reductionist process by which Descartes hoped to narrow all knowledge down to that of which he could be absolutely certain. For him, this was the conclusion, the absolute base at which he could pinpoint the only information he could not doubt. For us, this will be the starting point. We will, of course, have to accept on faith that we are not being possessed by an evil demon, having our brain placed in a jar or undergoing any other sort of fundamental deceit of basic reality. Consideration of such possibilities is only useful insofar as it could relate to us changing such circumstances (either by knowing, and thus making defunct, these forces or by somehow escaping such deceit -- which is impossible in the purest forms of this thought experiment), so once we have accepted that we exist as a real, conscious being, it naturally follows that we should accept the sensory...