When, in one's concern, one lets something be involved, one's doing so is founded on temporality, and amounts to an altogether pre-ontological and non-thematic way of understanding involvement and readiness-to-hand. In what follows, it will be shown to what extent the understanding of these types of Being as such is, in the end, also founded on temporality. We must first give a more concrete demonstration of the temporality of Being-in-the-world. With this as our aim, we shall trace how the theoretical attitude towards the 'world' 'arises' out of circumspective concern with the ready-to-hand. Not only the circumspective discovering of entities within-the-world but also the theoretical discovering of them is founded upon Being-in-the-world. The existential-temporal Interpretation of these ways of discovering is preparatory to the temporal characterization of this basic state of Dasein.
(b) The Temporal Meaning of the Way in which Circumspective Concern becomes Modified into the Theoretical Discovery of the Present-at-hand Within-the-world
When in the course of existential ontological analysis we ask how theoretical discovery 'arises' out of circumspective concern, this implies already that we  are not making a problem of the ontical history and development of science, or of the factical occasions for it, or of its proximate goals. In seeking the ontological genesis of the theoretical attitude, we are asking which of those conditions implied in Dasein's state of Being are existentially necessary for the possibility of Dasein's existing in the way of scientific research. This formulation of the question is aimed at an existential conception of science. This must be distinguished from the 'logical' conception which understands science with regard to its results and defines it as 'something established on an interconnection of true propositionsthat is, propositions counted as valid'. The existential conception understands science as a way of existence and thus as a mode of Being-in-theworld, which discovers or discloses either entities or Being. Yet a fully adequate existential Interpretation of science cannot be carried out until the meaning of Being and the 'connection' between Being and truthxix have been clarified in terms of the temporality of existence.1 The following deliberations are preparatory to the understanding of this central problematic, within which, moreover, the idea of phenomenology, as distinguished from the preliminary conception of it which we indicated by way of introductionxx will be developed for the first time.
Corresponding to the stage of our study at which we have now arrived, a further restriction will be imposed upon our Interpretation of the theoretical attitude. We shall investigate only the way in which circumspective
1 The italics in this and the following sentence appear only in the later editions.