In the course of the endeavor to uncover the conditions for the possibility of experience, Immanuel Kant and Edmund Husserl each develop a multifaceted, dynamic philosophy of time. For both thinkers, the concept of time arises from a tension between passive and active structures of the knowing subject. The central figure of the Enlightenment, Immanuel Kant, and the founder of phenomenology, Edmund Husserl, share the motive of exploring the conditions for the possibility of knowledge in order to legitimize it. In doing so, they develop a philosophy of time that traces the origin of the concept of time and the genesis of its diverse aspects back to the interplay of different subjective forms of behavior and structures. These can be described using the pairs of concepts receptivity and spontaneity in Kant, and passivity and activity in Husserl.