Ludwig Boltzmann's Bildtheorie and scientific understanding

Boltzmann's Bildtheorie, which asserts that scientific theories are `mental pictures' having at best a partial similarity to reality, was a core eleme nt of his philosophy of science. The aim of this article is to draw attenti on to a neglected aspect of it, namely its significance for the issue of sc ientific explanation and understanding, regarded by Boltzmann as central go als of science. I argue that, in addition to being an epistemological view of the interpretation of scientific theories Boltzmann's Bildtheorie has im plications for the nature of scientific understanding. This aspect has as y et been ignored because discussion of the Bildtheorie has been restricted t o the realism-instrumentalism debate. To elucidate my analysis of Boltzmann 's Bildtheorie concrete examples are presented, and the pragmatist and Darw inist roots of Boltzmann's view are discussed. Moreover, I propose to use Boltzmann's ideas as a starting-point for develo ping a novel analysis of the notion of scientific understanding, of which a brief impression is given. It shows that the study of Boltzmann's philosop hy is not only of historical interest but can be relevant also to modern ph ilosophy of science and to the methodology of theoretical physics.