  The presuppositional account of category mistakes maintains that category mistakes are infelicitous because they suffer from presupposition failure. Suppose, for example, that the predicate ‘is green’ triggers the presupposition that its subject has a color. This means that ‘The number two is green’ generates the presupposition that the number two has a color, a presupposition which is assumed to be false in nearly all contexts. A key way to test this presuppositional hypothesis is to check it against the various projection properties for presupposition, and indeed this test seems to lend support to the hypothesis: