These lectures attempt a phenomenological destruction of two problems issuing from life as the most basic phenomenon: the problem of the a priori and the problem of lived experience. Because “factical experience belongs in a completely primordial sense to the problematic of philosophy,” philosophy’s method must take the form of a destruction of transmitted senses, in which the meaningfulness of that experience has faded (verblasst). After examining six meanings of “history,” Heidegger argues that the problem of the a priori (primarily in Rickert, Simmel, and Scheler) is incoherent inasmuch as the sort of history in its sights, namely, the “objective past” is precisely “a theoretically idealizing and abstract determination,” one “that has left behind the concrete existence and the access to it” (64f, 72, 74). “The conclusion of the destruction of the a-priori problem is that transcendental philosophy goes down its secure path by forgetting the unum necessarium [the one thing necessary]: actual existence.”
Natorp’s and Dilthey’s sensitivity to the problem of lived-experience raises hopes that the world of the self would move into the center of concerns. Yet, despite the greater promise of Dilthey’s philosophy, neither philosopher gives actual existence its due, because “philosophy’s primordial motive” (to attain what is primordial) was forgotten, as philosophy slipped hopelessly into a “theoretical attitude” (169ff). By contrast, “philosophy has the task of upholding the facticity of life and fortifying the facticity of existence” (174).