A variety of commentators have explored the similarities between pragmatism and Thomas Reid’s Philosophy of Common Sense. Peirce himself claims his version of pragmatism either (loosely) is, or entails, a Critical Common-sensism, a blend of what is best in Kant and Reid. In this paper I argue for a neglected aspect of the relation between Peirce and Reid, and of each to common sense: linguistics. First, I summarize Peirce’s account of what distinguishes his common-sensism from Reid’s. Second, I argue for (...) the importance of appeals to linguistic universals by Reid as both a source for identifying common sense beliefs, and a basis for justifying them. While Peirce is occasionally tempted by such appeals, overall he is critical of appeals to language, especially as most Western philosophers have been familiar with a small set of (Indo-)European languages; say, English, French, German, Greek, Italian, and Latin. This leads to the third section, which concerns Peirce’s familiarity with major nineteenth century linguists, and his contention that the ‘peculiarity’ of Western European languages has impeded the development of logic and philosophy. In particular, I look at unpublished manuscripts where Peirce summarizes his own study of non-European languages, ranging from Arabic, to Ngarrindjeri, to Xhosa. Peirce was only an amateur linguist, and also aware of the challenges of doing cross-cultural linguistics through comparative grammar; e.g., the temptation to force unfamiliar languages onto the “Procrustean Bed of Aryan grammar” (CP 2.211). Nonetheless, this study left him suspicious of any claims of linguistic universals, and supported his anti-psychologism. That is, not only should logic and philosophy not be based upon psychology (at least as a special science), they should also be independent of linguistics. However, Peirce also advances something like the so-called Sapir-Whorf hypothesis, that language determines, or at least conditions, thought. The question now becomes what is the nature of a philosophy of common sense, even a critical one, without a common language, or possibly no commonalities across languages? (shrink)