The question of what ontological insights can be gained from the knowledge of physics (keyword: ontic structural realism) cannot obviously be completely separated from the view of physics as a science from an epistemological perspective. This is also visible in the debate about 'scientific realism'. This debate makes it clear, in the form of the importance of perception as a criterion for the assertion of existence in relation to the 'theoretical entities' of physics, that epistemology itself is 'ontologically loaded'. This is in the form of the assumption that things in themselves (independent of cognition, in an autonomous way) exist as so-and-so determined ones. This ontological assumption is not only the basis of our (naive) conception of knowledge, but also its indispensable premise, insofar as this conception is a fundamentally passive, 'receptive' one. This is true to the full extent of metaphysics, and to a not much lesser extent of epistemology. The interpretation of knowledge in the sense of 'description' seems to be without alternative. In the philosophy of science, this view is reflected in the emphasis on 'objectivity' as the essence of science, in the belief in 'induction' as the traditional method of science, and (ex negativo) in the problem of the 'theory laden nature of observation'. To these paradigms of epistemology, however, a further aggravating factor is added, namely the criterion of 'subjective certainty' as evidence of 'real' knowledge (only meaningful on the basis of the ontological premise mentioned above). Thus, due to its 'expertise' in matters of knowledge, epistemology becomes the 'prima philosophia'. But what is even more important, the real, holistic cognitive situation is transformed into a linear cognitive relationship, with the consequence of the 'transcendence' of the objects.
Now, on closer inspection, however, there is not too much in the expertise of epistemology, because it basically consists only of paradigms which, from the point of view of the holism of the real cognitive situation itself, are nothing more than relatively simplistic interpretations of this situation. However, we do not yet know what another conception of knowledge might look like (which is not surprising given the position of the phenomenon of knowledge in the hierarchy of phenomena according to their complexity). 'Certitude' as a criterion of cognition is thus excluded from the outset, and thus the linear relational model of cognition also appears as what it is, a gross distortion of the real, holistic situation of cognition.
The significance of this argumentation with regard to physics is that the linear epistemological model of cognition itself is a major obstacle to an adequate epistemological understanding of physics. This is because it is fixed 'a priori' to an object-related concept of knowledge, and to 'description' as the only mode of ('real') knowledge. The acceptance of the real, holistic epistemological situation is therefore, in my opinion, the condition for an adequate understanding of physics' heuristic access to objects, its transcendental, generalizing epistemological concept, as well as its ontological relevance and dimension.