This article offers a reading of Sartre's phenomenological ontology in light of the pre-modern understanding of ‘transcendentals’ as universal properties and predicates of all determinate beings. Drawing on Sartre's transcendental account of nothingness in his early critique of Husserl as well as his discussion of ‘determination as negation’ in Being and Nothingness, this article argues that Sartre's universal predicate of ‘the not’ (le non) could be understood in a similar light to the medieval scholastic conception of transcendentals. But whereas the (...) scholastics saw the transcendental properties of oneness, truth, and goodness as reflections of God's divine perfections, Sartre's predicate of the ‘not’ operates as an atheistic transcendental which signifies the non-being of God – that God is not. By comparing Sartre's phenomenological ontology to medieval theological metaphysics, this article not only highlights the atheist underpinnings of Sartre's entire ontological schema in Being and Nothingness but also offers a new way of interpreting Sartre as a systematic transcendental metaphysician. (shrink)