Critical commonsensism is a doctrine defended by Charles S. Peirce, mostly in response to Cartesianism.
While René Descartes proposed a method of inquiry that began with universal doubt (“Begin to see as absolutely false any belief in which there is a particle of doubt”), Peirce questioned the desirability and even the possibility of such a procedure. Peirce admits that in the course of a study, we might doubt something we initially thought was true, but in that case, we would have a positive, powerful reason to doubt it. Thus he advises us not to doubt in philosophy what we do not doubt in our hearts (CP 5.265).
Common sense is nothing more and nothing less than what we do not doubt in our hearts, the set of beliefs on which we rely in innumerable contexts. But in order to distinguish his understanding of universal reason from traditional forms (especially the universal reason of Thomas Reid and some others in the tradition of Duns Scotus), we must know that Peirce characterizes his doctrine as critical, as it is sometimes necessary to criticize even the strongest belief we have established. But such a critique could never be undertaken in the sense proposed by Descartes;
Peircian criticism is rather an ongoing step-by-step process in which we sift through our intellectual heritage, our preferences, relying on some parts of them to evaluate others.
Peirce‘s critical common sense is an attempt to recognize both the need for criticism and the solid authority of our commonly held beliefs.
