In this article, I propose a comparison between Natorp, Husserl, and Sellars that has a twofold aim. First, I ask to what extent Sellars’s perspective can be considered to be Neo-Kantian. Second, I demonstrate that the point of divergence among these three thinkers does not have to do with the role they ascribe to givenness in knowledge, but with the way they conceive the activity of thinking. Focusing on Husserl’s reading of Natorp’s theses concerning the subjective and objective ground of knowledge, I show that both Natorp and Husserl agree with Sellars on the limits of a positivistic and empiricist perspective that relies on what is given in perception for the justification of one’s epistemic beliefs. On the other hand, the differences between the three thinkers emerge as soon as we consider how they attempt to integrate the spontaneity of thinking into the sphere of intuition from a renewed Kantian perspective.