This chapter focuses on the extent to which J. P. Sartre endorses significant claim in the context of several interpretations in the literature. An evaluation of those interpretations will enable us to determine more precisely Sartre’s place within the transcendental tradition. Sartre’s claim concerning the primitive upsurge of the regions of being is better understood as a claim concerning the emergence of the for-itself and the in-itself, in their fundamental distinction as consciousness and world, but without any additional differentiations. The Mild Transcendentalist interpretation of Sartre places him at the center of the transcendental tradition. The reason why the form of phenomenalism attributed to Immanuel Kant and Sartre is qualified as ‘transcendental’ is that the claim made by phenomenalism holds in Kant’s and Sartre’s philosophies, but only from a transcendental perspective. According to Strong Transcendentalism, Kant and Sartre share transcendental phenomenalism – the view that, from a transcendental perspective, phenomena are reducible to mere representations.