Abstract
I shall explain the notions of propositions and states of affairs as they are understood in the current ontological debate and I shall briefly relate them to similar notions in Aristotle and some Medieval authors. In contrast with the point of view of some philosophers who identify propositions and states of affairs, I shall argue that they need to be sharply distinguished. I shall then move on to a problem for propositions and, above all, states of affairs, known as Bradley’s regress, and hint at discussions of this or analogous puzzles in the philosophical tradition before Bradley. Finally, I shall present my own approach to this issue, Fact Infinitism, focusing on why it would have been hardly acceptable before ontology came to have the Cantorian conception of the infinite at its disposal