With reference to an already existing and relatively widespread use of the expression in question, mathematical “thought experiments” (“TEs”) involve mathematical reasoning in which visualisation plays a relatively more important role. But to ensure an unambiguous and consistent use of the term, certain conditions have to be met: (1) Contrary to what has happened so far in the literature, the distinction between logical-formal thinking and experimental-operational thinking must not be ignored; (2) The separation between the context of discovery and the (...) context of justification is to be rejected, at least in one of the main senses in which it was defended by the logical empiricists and Popper (this excludes any position which, ascribing to mathematical TEs only a heuristic role, regards them an intermediate step to attain more traditional forms of rigour); (3) The distinction between mathematical TEs and formal proofs must be regarded as one of degree, and not as a qualitative one, although this distinction may be used in a de facto way for particular or local purposes. (shrink)

Based on the material in the Lakatos Archive, this paper reconstructs, and then re-assesses, Lakatos’ epistemological project by placing it in the context of the debate on the role of reason in the history of science, and of the justification of rationality as a normative notion. It is claimed that Lakatos’ most fruitful ideas come from a peculiar philosophical combination of Hegelian historicism and Popperian fallibilism. The original tension, however, cannot be ultimately resolved. As a consequence, the problems that Lakatos (...) has to deal with in his attempt to justify a set of genuinely epistemological canons of scientific rationality that are not reducible to psychology or sociology of knowledge stand as a warning for any normative philosophy of science that takes history at its face value.Author Keywords: Lakatos; History; Method; Rationality. (shrink)