 Mathematics, and Wittgenstein’s original thoughts on it, can undoubtedly be seen as another investigative anchor of middle Wittgenstein. Although it is clear that mathematics was of great interest to him in TLP, his thoughts on it became more enigmatic precisely in the middle period. Several “isms” are attributed to his view(s) on mathematics here – verificationism, formalism, and finitism, along with recognition of a “calculus conception” of mathematics. (Intuitionism, a favorite label for interpreters of Wittgenstein’s mathematics, is only identified in the Remarks on the Foundations of Mathematics (1937–1944) and after, i.e., in the later Wittgenstein.) It appears, however, that middle Wittgenstein’s dealings with mathematics in this period are, as claimed by Juliet Floyd (2005), constantly changing – and even that, not in any consistent developmental way but in “piecemeal and uneven” fashion. Indeed, along with written evidence of Wittgenstein's influence on and by mathematicians, we can identify the work on mathematics done particularly by the later Wittgenstein and even he of the post-Investigations period, as a substantial overturning of his early and middle conceptions of mathematics.