Abstract
In the Tractatus, Wittgenstein claims that tautologies 'say nothing'. Retrospectively, he explains that when he had called tautologies 'senseless' was trying to bring out that they possessed a zero quantity of sense. Insofar as it is the limit of a series of propositions of diminishing quantity of sense, tautology resembles a degenerate circular conic section. But it also resembles the result of a summing together of equal and opposite linear vector quantities. This essay contends first, that each of these models plays a role in shaping the Tractatus's conception of a tautology as saying nothing in virtue of possessing a zero quantity of sense and, second, that these models are not fully reconciled. Indeed, many of the puzzling features of the Tractatus's conception of logic arise from Wittgenstein's failure to bring about the needed reconciliation. These points are argued for by working through the development of Wittgenstein's views on these matters in the Wartime Notebooks and other pre-Tractatus writings.