 The epistemicist fits into the Thucydidean tradition of replacing indeterminacy with determinacy. Crispin Wright (2021, 393) compares the epistemicist’s postulation of hidden boundaries to the mathematical realist’s postulation of a hidden Platonic realm. Both the epistemicist and the mathematical realist add metaphysical infrastructure to ensure truth will transcend our means of proof. This infrastructure validates proofs of generalizations that are not constructed from examples. The impossibility of finding a witness for an existential generalization, such as ‘There is a youngest old man’, is compatible with there being a non-constructive proof.