 From the first camp Hand and Kvanvig (1999) protest that TKP has not been restricted in a principled manner—in effect, that we have been given no good reason, other than the threat of paradox, to restrict the principle to Cartesian statements. (An analogous claim may be made of Dummett’s DKP.) Tennant (2001b) replies to Hand and Kvanvig with general discussion about the admissibility of restrictions in the practice of conceptual analysis and philosophical clarification. By drawing analogies between his own restriction and others that are clearly admissible, he maintains that the Cartesian restriction is not ad-hoc. He also points out that TKP, rather than the unrestricted KP, serves as the more interesting point of contention between the semantic realist and anti-realist. The realist believes that it is possible for truth to be unknowable in principle. Fitch’s reasoning, at best, shows us that there is structural unknowability, that is, unknowability that is a function of logical considerations alone. But is there a more substantial kind of unknowability, for instance, unknowability that is a function of the recognition-transcendence of the non-logical subject-matter? A realist decrying the ad hoc nature of TKP (or DKP) fails to engage the knowability theorist at the heart of the realism debate.