Abstract

« Good sense is, of a all things among men, the most equally distributed ». This sentence stands out as one of the most famous in Descartes’ philosophy. We often consider this simple statement a clear break from the « obscurity » of the so-called scholastic tradition. However, some contemporary commentators of the Discourse on Method, such as father Poisson, understood this sentence as an implicit reference to an ancient scholastic theory, called the theory of intensio et remissio formarum. This theory states that where the accidental qualitites of a substance undergo increase or decrease, i. e. variations in intensity, the essential qualities of a substance do not. According to these commentators, Descartes uses it as a way to prove that Thought, or « good sense », knows no variation in one’s mind, that it is distributed equally amongst all men, and that the soul « always thinks ».In the present article, we recall the meaning of this scholastic theory and we show how it was perceived as a key to understanding and justifying Descartes’claim about the substantiality of thought. We then show how, a few years later, John Locke uses the very same theory to argue against Descartes that the life of the mind is in fact subject to variations in intensity.