ABSTRACT
This chapter focuses on an important shift that challenged the mainstream epistemology of the Enlightenment. It looks at the re-evaluation of the function of hypotheses in the construction of scientific systems. The main figure discussed is Condillac, who dealt with this topic in the Traité des systèmes (1749) and later on in the Cours d’études (1775). It will be shown that he most probably relied on the reassessment of hypotheses made by Émilie Du Châtelet in the Institutions de physique (1740, 1742). What was at stake in both cases were not simply questions of methodology but also the status that was to be given to Newton’s controversial force of attraction.
