Ludwik Fleck is a pioneer of the contemporary social constructionist trend in scientific theory, where his central concept of thinking style has become standard fare. Yet the concept is too often misunderstood and simplified with serious consequences not only for Fleck studies. My essay situates Fleck’s concept of thinking style in the historical context of the 1920s and ‘30s, when the notion of style was first applied to the natural sciences, in order to illustrate the uniqueness of Fleck’s concept among (...) the uses of style by his contemporaries and, finally, to examine the epistemological, methodological, and political consequences of this distinction. (shrink)