 (That is—with ‘2^\(n\)’ representing ‘2 to the power \(n\)’—‘[2^(2^(2^(2^(2^2))))]\(+1\) is prime’; cf. Tennant, 1997 p. 152.) They cannot deny the sentence exists, for there is the token before our very eyes. But there are strong grounds for thinking that no concrete proof or disproof will exist, for the only methods available may use up more time, space and material than any human could have at her disposal, perhaps than actually exists. There are countless sentences with this property: concrete tokens of them exist but no concrete proof or refutation actually exists, none that a human could manipulate as a meaningful utterance anyway. (Cf. Boolos, 1987.) Formalists of Goodman and Quine’s persuasion seem forced to the conclusion that sentences like the above, sentences which are decidable in the usual formal sense, are neither true nor false, since neither (concretely) provable nor refutable. To embrace this view, however, would be to butcher mathematics as currently practiced; such a consequence should rather be viewed as a reductio ad absurdum of their position.