On the methodology of informal rigour: set theory, semantics, and intuitionism

Abstract

In his paper Kreisel adumbrates a crucial insight into the nature of mathematics and foundations of mathematics by focusing on the notion of "informal rigor." It seems to me that philosophy of mathematics should pay much more attention to this notion than has been the case.(Isaacson, 2011, p. 13) * Forthcoming in Intuitionism, Computation, and Proof: Selected themes from the research of G. Kreisel, M. Antonutti Marfori and M. Petrolo (editors), Springer. Please do not cite without permission.