In this chapter two theses in particular will be developed. First: the "ontology" of the TLP stands within the framework of the theory of sense, and does so in two respects, which is why one can speak of a two-layered "ontology" of the TLP: (1) as the grounding of the possibility of the proposition's relation to and description of the world through the assumption of the OBJECT; it will become apparent that the OBJECT of the TLP is not conceived as a (pre-)given entity, but as a conception of purpose for the determination of reality that is available within a system of world-description, or even more or less "freely" selectable – and (2) as "ontology" in the sense of a transfer of concepts of the theory of sense to the world that is describable, i.e. linguistically graspable, in accordance with "ontology" (1) (e.g.: to the significant proposition there corresponds "ontologically" the state of affairs; to the true proposition, the fact). The second thesis regarding the "ontology" of the TLP is that both the "ontology" (1) of the OBJECT and the "ontology" (2) of the ontological analogues of concepts of the theory of sense are built on the same principle of the priority of the proposition over its constituents as the theory of sense: for "ontology" (1) grounds the possibility of the proposition as relation to and description of the world, while "ontology" (2) is the translation of the concepts of the theory of sense of the proposition onto reality.

The view that the "ontology" of the TLP is conceived in terms of the logic of language is held, for example, by Lorenz: only through an "interpretation of the picture theory essentially independent of the theses of 'logical atomism'" does one succeed in "convincing oneself that a 'realistic' reading of the picture theory, caught up in the opposition of realism and idealism, misses the point of Wittgenstein's semantics. In particular, only then does it become possible to interpret the so-called 'ontological' first part of the 'Tractatus' as an invariant representation of the subsequent 'logical' parts, which deal essentially with statements, and thus to understand it reasonably." – Further, Wallner: "...the function of Wittgenstein's 'ontology' – should it prove meaningful to speak of such a thing at all – has nothing of the unquestioned self-evidence with which a declared or 'practical' empiricist is accustomed to understand such a thing. But this appearance of self-evidence has so far often prevented the question of the function of 'ontology' in the Tractatus from being posed radically."