ABSTRACT. Heidegger's thought is that metaphysics is prior to logic, in that an understanding of logic is required to have an adequate theory of logic. Heidegger, while defining the act of synthesis, resorts to the field of pure sensibility, as a siege of the ecstatic temporality. Heidegger recognizes the importance of the finitude of human cognition and he traces the source of this finitude to human intuitional cognition.