Heidegger’s philosophy is often maligned as mystical or obfuscating. This is because of the great generality of the terms with which he is working, e.g., “being”, “world”, etc. But these terms are not found to be too general when we investigate them in a concrete phenomenological manner, i.e., from their origin in the primordial experience of Dasein. The reason or prompt or solicitation for such an investigation by Heidegger is a residual dissatisfaction among people with the modern abstract conception of mind as an isolated entity or atom. In this Cartesian sense, the mind is supposed to exist independently of the world it studies. This Cartesian formulation of the mind-world relation made possible modern mathematical physics along with the correlated engineering and technological attitude which has shaped the modern approach to nature. The key to understanding Heidegger’s philosophical project is thus as a kind of neo-Aristotelian counterpoint, responding to what we have lost by way of modern mathematical physics. The latter approach to nature is in Heidegger’s analysis essentially a technological framework recognizing no essential or meaningful place or ground or telos for any of its objects. In this world-view the things of nature — as well as human beings — are rendered into abstract variables, abstract objects, stripped of any essential nature or place of being. Modern mathematical physics is in this sense — ironically, despite its own claims to the contrary — a kind of alienating anti-naturalism. The phenomenological analysis of Dasein in Being and Time is intended to lay the groundwork for retrieving and restoring some Aristotelian sense of ontological place or home for Dasein despite the impossibility of simply returning to an Aristotelian teleological cosmos.