[What is thinking inside the individual? Figurations of Collectivity in Ludwik Fleck, Tadeusz Bilikiewicz, and Ludwig Gumplowicz].

"What thinks in man, is not he himself, but his social community." These words by the early sociologist Ludwig Gumplowicz (1838–1909) were quoted several times by Ludwik Fleck (1896–1961) and seem to be in complete agreement with his own theory of thought collectives. The assumption that even scientific ideas were not so much generated by the scientist as an autonomous individual but rather by and within the social environment was still considered provocative by Fleck in the 1930s. This article will explore the implications of this assumption by comparing Fleck with Gumplowicz as well as with Tadeusz Bilikiewicz (1901–1980), a psychiatrist, philosopher and historian of medicine working like Fleck in the cultural milieu of Lwów/Lemberg.