In recent years, the philosophy of Ludwig Boltzmann has become a point of interest within the field of history of philosophy of science. Attention has centred around Boltzmann's philosophical considerations connected to his defense of atomism in physics. In analysing these considerations, several scholars have attributed a pragmatist stance to Boltzmann. In this paper, I want to argue that, whatever pragmatist traits may be found in Boltzmann's diverse writings, his defense of atomism in physics can not be analysed this way. In other words, I wish to show that he did not defend atomism as "preferable for its practical virtues", as has been alleged.¹ On the contrary, Boltzmann considered the atomist picture to be indispensable — more precisely, an indispensable prerequisite for making the application of continuous differential equations an understandable enterprise.