 How, then, to best demarcate the middle Wittgenstein? The wide date recognition, all along from 1929 (or even earlier) to 1944 (the time when Wittgenstein began the final revision of PI) might seem too obvious, though it can house readings of the continuity-between-early-and-later-Wittgenstein school persuasively. Such is work by, for instance, Joachim Schulte (1992), who notes a middle Wittgenstein already in the TLP leading all the way to later Wittgenstein’s key treatments of grammar or mathematics. The opposite extreme, of pinpointing one point in time as expressing a sole significant transformation, seems too summary. This strategy is adopted, for example, by the Hintikkas (1986b) regarding the year 1929 or by Kienzler (1997) concerning a transitional break in 1931. Then there are the various more moderate determinations, which adopt a time-span of a few years, usually sometime between 1929 and 1935, explaining their delineations by philosophical interpretations of the texts and contexts of those times. Such are: O. K. Bouwsma (1961), who points to the period of the Blue and Brown Books (1933–35); P. M. S. Hacker (1986), who follows a two year period – 1929–1930 – as the middle Wittgenstein “bridge”; Alois Pichler (2004), who recognizes a middle Wittgenstein in 1930–1935 based on Wittgensteinian styles; or David Stern (1991), who briefly gives the demarcation of “the late 1920s and early 1930s.”