Division I of Being and Time contains the complete account of early Heidegger's quarrel with and departure from the philosophical tradition. In spite of the attempts by many, beginning with Husserl, to incorporate Heidegger's insights into a more traditional framework, that departure was a radical one. For Heidegger the tradition that began in ancient Greece finds what may be its ultimate expression in Husserl's phenomenology.

As Føllesdal and his successors have argued, Husserl's phenomenology can be understood as the joint product of two influences. From Brentano he took the insight that the defining characteristic of consciousness is its intentionality - that is, its “of -ness” or directedness toward some object. But the model he uses for understanding this intentionality or directedness is essentially the same as Frege's model of linguistic reference, with the basic notion of meaning or sense (Sinn) suitably generalized so as to apply to all acts of consciousness, linguistic and nonlinguistic. As Figures 1 and 2 suggest, just as Frege distinguishes the sense of a linguistic expression from its referent, so Husserl distinguishes the meaning of a conscious act from the object it is about. For both, the meaning is that in virtue of which we can refer to or intend objects.