What One May Come to Know Johan van Benthem Abstract: Fitch's 'paradox of the Knower' shows that verificationism in the appealing version "everything that is true may be known" is inconsistent. We give an even stronger dynamic version: "everything that is true may come to be known", and point out its connections with the 'learning problem' for statements in update logics. Moreover, we show how different natural versions of the verificationist thesis hold for different classes of epistemic statement, and that these classes are all decidable in basic epistemic S5. Keywords: knowledge, update, epistemic logic, dynamic logic, learning, Fitch Paradox