 Since Fitch’s reasoning is intuitionistically valid through line 10, the intuitionist anti-realist must accept that no truths are unknown: \(\neg \exists p(p \wedge \neg Kp)\). Arguably this is harmful enough, for it appears that the anti-realist cannot give credence to the truism that (individually and collectively) we are non-omniscient. Williamson responds that the intuitionist anti-realist may naturally express our non-omniscience as “not all truths are known”: 