Such 'presupposing' has nothing to do with laying down an axiom from which a sequence of propositions is deductively derived. It is quite impossible for there to be any 'circular argument' in formulating the question about the meaning of Being; for in answering this question, the issue is not one of grounding something by such a derivation; it is rather one of laying bare the grounds for it and exhibiting them.1
In the question of the meaning of Being there is no 'circular reasoning' but rather a remarkable 'relatedness backward or forward' which what we are asking about (Being) bears to the inquiry itself as a mode of Being of an entity. Here what is asked about has an essential pertinence to the inquiry itself, and this belongs to the ownmost meaning [eigensten Sinn] of the question of Being. This only means, however, that there is a way—perhaps even a very special one—in which entities with the character of Dasein are related to the question of Being. But have we not thus demonstrated that a certain kind of entity has a priority with regard to its Being? And have we not thus presented that entity which shall serve as the primary example to be interrogated in the question of Being? So far our discussion has not demonstrated Dasein's priority, nor has it shown decisively whether Dasein may possibly or even necessarily serve as the primary entity to be interrogated. But indeed something like a priority of Dasein has announced itself.
¶ 3. The Ontological Priority of the Question of Being
When we pointed out the characteristics of the question of Being, taking as our clue the formal structure of the question as such, we made it clear that this question is a peculiar one, in that a series of fundamental considerations is required for working it out, not to mention for solving it.
1 '... weil es in der Beantwortung der Frage nicht um eine ableitende Begründung, sondern um aufweisende Grund-Freilegung geht.' Expressions of the form 'es geht ... um ...' appear very often in this work. We shall usually translate them by variants on '... is an issue for ...'