I examine the variety of Kuhn’s notions of incommensurability, including methodological, semantic and observational incommensurability as found in the Structure of Scientific Revolutions, and local incommensurability as found in later publications. I argue that through these various presentations, Kuhn establishes reasons to criticize and reject the correspondence theory of truth that is predicated on a mind-independent world. I show that under both observational incommensurability and local incommensurability, Kuhn provides reasons to criticize the epistemic assumptions in truth as correspondence. I maintain that for both semantic incommensurability and local incommensurability, Kuhn assumes the conception of language as the universal medium. I contend that this view of language, together with Kuhn’s rejection of a neutral language, provides reasons to challenge the linguistic assumptions behind the correspondence theory. I suggest that, given the challenges his thesis of incommensurability raises against truth as correspondence, Kuhn rejects the correspondence theory and instead considers alternative theories of truth.

This essay was triggered by the sudden rise in popularity of Jordan Peterson in 2017. As his platform grew, I received frequent queries on when we were going to “debunk” Peterson, “put him in his place,” “refute his ideas,” and so forth. There were a few voices of support but most people seemed to prejudge Peterson based on a handful of snippets from his writings, and especially video clips taken out of context. Peterson seems to engender passionate emotions (both for and against) his ideas presented in YouTube videos, podcasts, books, and his multi-city lecture tour routinely selling out large theaters. Given all this media attention, I felt it was time to examine with a skeptical eye Jordan Peterson’s ideas and, especially, the phenomenon surrounding him, so this was my introduction to a special issue of Skeptic we published in 2018 on the man.