Genesis and development of the “medical fact”. Thought style and scientific evidence in the epistemology of Ludwik Fleck

A diagnosis based exclusively on the so-called scientifi c evidence does not take into account the problem of the theoryladenness,widely debated in Twentieth Century epistemology. The theory of knowledge developed by Ludwik Fleck,physician and philosopher active in the 30s, can still be useful for shedding light on how psychiatric diagnoses areinfl uenced by a specifi c thought style that directs the observations and affects the development of knowledge and theformation of connections between concepts.