The article investigates the way in which Peter Mittelstaedt has been contributing to the philosophy of physics for half a century. It is shown that he pursues a path between rationalism and empiricism in the sense of Erhard Scheibe’s philosophy of the physicists. Starting from Kant’s a priori he gives a rational reconstruction of the conceptual revolutions of 20th century physics. The central topic of his philosophy of physics is the quest for semantic self-consistency, which for quantum mechanics is a (...) hard nut to crack. (shrink)

In his Critique of Pure Reason, in the chapter on the antinomy of pure reason, Kant not only argues that aprioristic cosmology is doomed to failure; he also implies that empirical knowledge about the universe is impossible. Today, such a negative verdict about the possibility of cosmological knowledge seems implausible because physical cosmology has made substantial progress. In particular, the spatiotemporal extension of the universe now seems a matter of empirical investigation in which models figure centrally. But I think it (...) is worth considering the possibility that Kant got something right and that he offers insights that can help us to better understand problems in present-day cosmology. In this article, I explore a striking coincidence: according to both Kant and current wisdom, cosmology faces a serious underdetermination problem regarding the spatiotemporal extension of the world. As a closer analysis reveals, however, Kant and modern cosmology differ on the reasons why underdetermination arises. In current cosmology, underdetermination follows from laws that are knowable a posteriori, and not only from the very idea of cosmological knowledge, as Kant would have it. This suggests that the current underdetermination problem is not fully a Kantian one. (shrink)