The goal of both Russel’s Principia (1910) and Frege’s Begriffsschriftis (1879) ["a formula language, modeled on that of arithmetic, for pure thought."] was essentially to defend the thesis that mathematics can be reduced to logic, that mathematical truths are logical truths. These works put forward the logicist claim that logical knowledge enjoys a privileged status in comparison with other types of knowledge about the world.
Likewise, standing on the shoulders of these two philosophers/logicians, Wittgenstein’s goal in his Tractatus was primarily that of eliminating from philosophy the alleged “nonsense” deriving from philosophy's distorted uses of language by attempting to describe/show the limits of thought and language, sense and meaning. Adding his picture theory of meaning/language, which is arguably but a more sophisticated version of the Correspondence Theory, arguing that the logical structure of the world is somehow mirrored in the logical structure of rationality. And declaring that “What can be said at all can be said clearly; and whereof one cannot speak thereof one must remain silent.”
While (until recently*) the arguably common theses of these works largely succeeded in causing the then world of thought and knowledge to pivot in a new direction, i.e. away from Hegelian idealism and grand metaphysical system building in general and toward conceptual elucidation and logical clarity, I wonder how, approaching the centennial of the Tractatus’ publication, in the decidedly Rortian neo pragmatic post-positivism of 2021 (in part ushered in by Witgenstein's own Philosophical Investigations), aside from the instrumental methods of a predicate calculus (particularly useful to, say, computation, AI, etc. ), one would usefully characterize these works’ lasting influences and failures to epistemology. Their legacy.
(*I say “until recently” because of the resurgence of [a now post-positivist] metaphysical realism, so typical in the trending (arguably Hegelian) lexicon of “structural” and “systemic” objects/[arti]facts.)
