Heidegger interpreted Kant’s Critique of Pure Reason, in an effort to ground metaphysics. This study aims to analyze the relationship between self and time as the key point of that interpretation with reference to Kant and Heidegger. Unlike Kant, Heidegger focuses on and awards significance to the concept of time in order to attain ontological knowledge. By doing so, the philosopher pushes the boundary that Kant draws between knowable and unknowable. In order to reveal how Heidegger achieves that, one should first shed light on how self and time relate to the concepts of transcendency, infiniteness, finiteness, thinking and self-consciousness. This article, which also aims to interpret the said relationality, consequently, holds that Heidegger, reduces the distance between humans and reality through his attempt to ground metaphysics.