Abstract

Heidegger claims in Being and Time that the metaphysically certain knowledge provided by Descartes's Meditations is an impossibility and that Descartes's clear and distinct ideas, as well as the lumen naturale, are figurative expressions for the more primordial disclosedness or "clearing" of Dasein. In place of Descartes's form of clarity, clearness and distinctness, Heidegger urges his own form, disclosedness. The dissertation addresses first what Descartes's and Heidegger's forms of clarity are, second whether Heidegger's argument succeeds in showing that Descartes's form is a modification of his own, and third what the notion of clarity is and how it can be achieved. ;Despite the wide philosophical differences between Descartes and Heidegger, their central cases of clarity, the intuition of God, and Dasein's resolution possess a common form. Clarity in its primary signification--the notion of clarity--is the momentary apprehension of a unique, concrete, whole entity, in terms of which other entities can exist and can be what they are, and in terms of which there can be truth. ;That their central cases of clarity possess this common form is a result of both inquiries' employing the order of discovery in securing foundations. Both forms of clarity are fundamental apprehensions of what is real and true. Yet because Descartes's and Heidegger's inquiries begin with different concerns and different questions, they reach different foundations secured through different, though structurally similar, fundamental apprehensions of what is real and of what is true. Whatever is real and true is determined by either system and is contained within it. ;Despite Heidegger's attempt to ground Descartes's ontology on his fundamental ontology, and despite his interpretation of the "cogito, sum" in his exposition of the mathematical projection of nature, his ontology cannot ground Descartes's. Just as their foundations differ so too do the realities they admit. The two systems remain intact, independent, and each possessing its own specific form of clarity