On two formalizations of the principle of knowability de re

Abstract

The article is devoted to the problem of logical representation (formalization) of the principle of knowability de re. The principle says that any true proposition can be known de re. The aim of the paper is of a critical character. Two formalizations of the principle of knowability de re are examined, namely ones suggested by Edgington and Proietti, and it is shown that both do not solve the problem. I argue that Edgington’s formalizations does not work without an intuitively appealing interpretation of the actuality operator within situation semantics, and that Proietti’s formalization cannot be applied to quantified propositions. This shows that the formalization of the principle remains an open problem.