Heidegger’s interpretation of Kant (Kant and the Problem of Metaphysics, 1929) can be seen as an attempt to force on Kant Heidegger’s own doctrine of fundamental ontology as it was expounded through the analysis of human being insofar as it is unique, the so-called ‘Dasein’ of Being and Time (1927). ‘Fundamental ontology’ was Heidegger’s attempt to explicate the nature of being through the examination of Dasein’s relationship to its own temporality. Shortly after the publication of his book on Kant Heidegger renounced the possibility of gaining an ultimate understanding of being against the horizon of time. Since Heidegger himself abandoned the project of fundamental ontology, the object of the present investigation is not primarily an attempt to criticize Heidegger’s interpretation. Rather, I try to show that Heidegger’s analysis of the two core aspects of fundamental ontology, that I call ontological and intellectual finitude, constitutes a lasting acquisition for philosophy regardless of whether or not one chooses to adopt fundamental ontology. I argue that the conjunction of ontological and intellectual finitude grants a portrait of the philosopher as what Heidegger calls ‘authentic Dasein’, and thereby gives a valuable interpretation of the nature of philosophy itself as human activity.