Ivan Welty

Statements of degree appear to falsify basic doctrines in Tractatus Logico-Philosophicus. I offer a fresh formulation of the challenge and assess a solution proposed on Wittgenstein’s behalf by Sarah Moss. I find that Moss’s proposal fails. The proposal rides in part on novel interpretations of pronouncements by Wittgenstein on the nature of the elementary proposition. I find that the interpretations cannot be sustained but that Moss’s textual case hints at important and overlooked features of the Tractarian program. I develop Wittgenstein’s comparison of propositions to measuring instruments and apply it throughout, showing that it captures philosophical commitments in Tractatus that otherwise tend to slip from view.

Frege's account of indirect proof has been thought to be problematic. This thought seems to rest on the supposition that some notion of logical consequence ? which Frege did not have ? is indispensable for a satisfactory account of indirect proof. It is not so. Frege's account is no less workable than the account predominant today. Indeed, Frege's account may be best understood as a restatement of the latter, although from a higher order point of view. I argue that this ascent is motivated by Frege's conception of logic