 Willard Van Orman Quine  combined behaviorist psychology with a normative conception of logical form similar to Carnap’s. The result was an influential view according to which there is no fact of the matter about which proposition a speaker/thinker expresses with a sentence of natural language, because talk of propositions is (at best) a way of talking about how we should regiment our verbal behavior for certain purposes—and in particular, for purposes of scientific inquiry. On this view, claims about logical form are evaluative, and such claims are underdetermined by the totality of facts concerning speakers’ dispositions to use language. From this perspective, mismatches between logical and grammatical form are to be expected, and we should not conclude that ordinary speakers have mental representations that are isomorphic with sentences of a Fregean Begriffsschrift.