This article deals with the relationship between philosophy and science in the writings of Karl Jaspers and with its reception in the wider scholarly literature. The problem discussed is how to characterize the relationship that exists between science—defined on pure Kantian grounds as a universally valid knowledge of phenomenal objects—and philosophy—conceived by Jaspers as the transcending mode of thinking of personal Existenz rising towards the totality and unity of Being. Two solutions to that problem arise from Jaspers’s writings. The oppositionist view is based in his earlier philosophy of Existenz. It describes the discrepancy between determinateness, bestowed by science to its objects, and freedom of self-determination, which is both a synonym and a condition of possibility for Existenz. The reciprocal view is based in Jaspers’s later works, where he focuses on exploration of his concept of Being (das Umgreifende). By contrast with most of Jaspers’s commentators, the present interpretation is anchored in a developmentaland contextual understanding of Jaspers’s thought. Showing the transcendental background of this topic, the proposed interpretation allows us to abstain from viewing the two solutions as incoherent or contradictory and instead to see them as constitutive of a single philosophical course.