International audienceThis article studies Buridan’s treatment of the paradoxes which arise from the use of verbs “signifying acts of the cognitive soul”. We can find his analyses mainly in the Sophismata (IXth treatise of Summulae logicales), and in the IVth treatise, dedicated to suppositions. However they can be put in relation with some aspects of the theory of the soul. John Buridan examines many sophisms created by these phenomena. Some of them permit to study simple acts of cognition, and especially the variations between singular and universal apprehension of a thing. Others concern complex acts of knowledge, when the cognitive verb governs propositions; they require logical analyses, especially comparisons between compound and di...