Abstract

`Proto-idea' was a central concept in the thinking of the Polish microbiologist and philosopher of science Ludwik Fleck (1896–1961). Based on studies of the origin of the modern concept of syphilis, Fleck claimed that many established scientific facts are best understood as interpretations of pre scientific, somewhat hazy `proto-ideas' in the framework of a certain `thought-style'. As an example,Fleck saw the modern knowledge of infection as an interpretation of the ancient proto-idea of diseases as caused by minute `animalcules'. However, the epistemological aspects of the concept of proto-ideas have only been sparsely developed and discussed by Fleck and his critics. This paper attempts to bridge the gap. Firstly, I reconstruct the concept of proto-ideasin the context of Fleck's constructivist theory of knowledge. Secondly, I illustrate the relation between Fleck's concept of proto-ideas and his nominalist view on medical taxonomy. Finally, I discuss four philosophical problems implied by Fleck's concept of proto-ideas: (a) the problem of combining two conflicting perspectives on the history of science (b) the problem of accounting for the notion of` continuity' within a non realist theory of knowledge (c) the problem of ascribing no truth-content to proto-ideas, and (d) the problem concerning the non-neutrality of the analyst's viewpoint