Heidegger's concern with securing the proper access to Dasein leads him to assess Husserl's phenomenological understanding of the phenomenon of intentionality within the context of its principle "to the matters themselves'. Specifically, he is keen to find out whether the phenomenal priority and originality that is ascribed to intentionality by Husserl is based on a justified appeal to the phenomena involved in its manifestation. In order to find this out, Heidegger maintains that he must determine if both the entity that Husserl's phenomenology understands as manifesting the structure of intentionality, as well as this phenomenology's understanding of the Being of this structure, emerge from out of a genuine encounter with each in their respective modes of phenomena, i.e., as phenomena in the ordinary and deformalized phenomenological senses. What is at issue here, for Heidegger, then, is an "immanent critique of phenomenological research" (HCT, 102/140), which will make it "clear that the question of Being is not an optional and merely possible question,but the most urgent question inherent in the very meaning of phenomenology itself" (HCT, 115/158). Which is to say, Heidegger's inquiry into Husserl's understanding of intentionality will be guided by the aim of finding out whether the mode of being of the entity which manifests the phenomenon of intentionality, Dasein, has been exhibited in the way of access most proper to this entity, when it is understood in accord with Husserl's understanding of intentionality.