Descartes’ epistemology assigns a central role to mental contents or ideas. Language [loquela, langue] plays a secondary and auxiliary role – that is, for the storage and communication of previously constituted thoughts. From this perspective, the possession of “ideas” is seen as independent of, and prior to, their linguistic expression. Moreover, the direct inspection of ideas provides the criterion of meaning for a correct usage of words.

1.Ideas and Language

As a philosophical innovator, Descartes is bound to make use of a preexisting vocabulary – either ordinary or philosophical – while providing it with new meanings. Thus, in the Second Meditation, after gradually discovering the true notion of mind, he finally applies some common and traditional terms to it, but he is eager to stress that now they are given a novel and correct meaning: “I am … in the strict sense only a thing that thinks; that is, I am a mind, or intelligence, or intellect, or reason, words whose meaning I have been ignorant of until now” (AT VII 27, CSM II 18). Conversely, a few lines below he warns us that our language often perpetuates confused ways of thinking: “Although I am thinking about these matters within myself, silently and without speaking, nonetheless the actual words bring me up short, and I am almost tricked by ordinary ways of talking [decipior ab ipso usu loquendi]” (AT VII 31–32, CSM II 21). He adds that “one who wants to achieve knowledge above the ordinary level should feel ashamed at having taken ordinary ways of talking as a basis for doubt” (AT VII 32, CSM II 21). Actually, ordinary language incorporates in its meanings the confused notions originating from infancy. Moreover, it can mask our lack of understanding. The warning against the abuses of language is systematically developed in Principles I.74: