§13. Characterization of the ontological distinction between res extensa and res cogitans with the aid of the Kantian formulation of the problem
The discussion of the first two theses led us in each case to tum the question of the meaning of actuality, or of thingness and actuality, back to the Dasein's comportments. Using as a clue the intentional structure of these comportments and the understanding of being at each time immanent in each comportment, we were thus enabled to ask about the constitution of the being to which in each instance the comportment comports: the perceived of perception in its perceivedness, the product (producible) of production in its producedness. The two comportments at the same time revealed an interconnection. All producing is oriented by visual awareness; it is perceptual in the broadest sense.
The necessity of such a reversion to the Dasein's comportments is generally an indication that the Dasein itself has a distinctive function for making possible an adequately founded ontological inquiry in general. This implies that the investigation of the Dasein's specific mode of being and ontological constitution is unavoidable. Furthermore, we stressed repeatedly that all ontology, even the most primitive, necessarily looks back to the Dasein. Wherever philosophy awakens, this entity already stands in the sphere of vision, even if with a different clarity and with varying insight into its function for fundamental ontology. In antiquity and the Middle Ages
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