In his Meditations René Descartes famously enquires what can be surely known without doubt. Frequently not taken into account though, is the rather practical side to his argument, that culminates in the proof for the certain knowledge of god. In his last meditation Descartes concludes that one's bodily senses, while imperfect, generally give an adequate perception of reality. Certainly enough to maneuver everyday life. It seems then, that the goal of his radical delve into the foundations of knowledge was to expand on the possibilities of a good life, and underscore - even justify - the sensations and beliefs that come with it. In that sense, his proposed categorical split between thinking and extended thing, as two substances of human being, seems rather peculiar. While for Descartes secure knowledge is finally rooted in the idea of a complete being whose grace and goodness humans can grasp through their being res cogitans, the question arises: did the concept of god really prove our own experience here, or does the argument really follow the other way around? After all, the perfect being is inferred from the intuition of one's own fallibility - an intuition that takes its immediacy not from present experience per se, but from its negation, unfolded into the general method of critical doubt. Body and mind have hard to escape limitations, which can hardly be refuted. But where, then, does the plausibility of a perfect being, thought of as our supplemental and sublime origin, come from? Should it be explained as the psychological traces of idealized parental figures, a mere remnant of early childhood development - or can a more compelling argument be made, that finds in all abstract ideas our general motivation to confront our fallibility, rejection, hardship and death with their negation? This topic, then, promises to shine light on the nexus of the substance division: the principles of intellectual abstraction and the libidinous basis of the individual life.