science neither contain the "proper" ontological concepts of the being of those beings concerned, nor can such concepts be attained merely through a "suitable" extension of these fundamental concepts. Rather, the originary ontological concepts must be attained prior to any scientific definition of fundamental concepts. For it is from those ontological concepts that it first becomes possible to assess the restrictive way - which in each case delimits from a particular perspective - in which the fundamental concepts of the sciences correlate with being, which can be grasped in these purely ontological concepts. The "fact" of the sciences, [30 {GA 9 133}] i.e., the factical subsistence of an understanding of being, which is necessarily contained in them as in all comportment toward beings, can neither be the authority that grounds their a priori, nor can it be the source for knowledge of that a priori. Rather, it can only be one possible occasion for pointing us toward the originary ontological constitution of, for example, history or nature. Such a pointer must itself remain subject to a constant critique that has already taken its guidelines from the fundamental problematic of all questioning concerning the being of beings.

The possible levels and variations of ontological truth in the broader sense at the same time betray the wealth of originary truth lying at the ground of all antic truth.17 Unconcealment of being, however, is always truth of the being of beings, whether such beings are actual or not. Conversely, in the unconcealment of beings there already lies in each case an unconcealment of their being. On tic and ontological truth each concern, in different ways, beings in their being, and being of beings. They belong essentially together on the grounds of their relation to the distinction between being and beingsa (ontological difference).b The essence of truth in general, which is thus necessarily forked in terms of the antic and the ontological,c

a First edition, 1919: The ambiguous nature of this distinction: in terms of what has gone before, a step toward its overcoming, and yet a fateful link back to it that obstructs every path toward the originary "unity" and hence also to the truth of the distinction.

b First edition, 1919: On this, cf. the lecture course of summer semester 1927 "The Basic Problems of Phenomenology," §22, where the term is first conveyed publicly. The conclusion corresponds to the beginning where Kant's thesis concerning "being" (the "is"), namely, that it is not a real predicate, is discussed. The discussion occurs with the intent of first getting a view of the ontological difference as such, and of doing so in coming from ontology, ontology itself, however, being experienced in terms of fundamental ontology. This lecture course as a whole belongs to Being and Time, Part I, Division Three, "Time and Being."

c First edition, 1919: Here the essence of truth is conceived as "forked" in terms of the "distinction" as a fixed reference point, instead of the contrary approach of overcoming the "distinction" from out of the essence of the truth of beyng, or of first thinking the "distinction" as beyng itself and therein the beyings of beyng [das Seyende des Seyns] - no longer as the being of beings.