 ‘True’ language use, as opposed to the mere production of sound, is according to Cordemoy a matter of “giving signs to one’s thoughts” (1968 196). Language is on his account an artificial system of signs, the purpose of which is to communicate our thoughts, the words standing as their representatives, to one another. It is the creative aspect of language which demands the presence of a rational soul. True speech requires two things, says Cordemoy: “the formation of the voice, which can only come from the body, and the signification or idea that is joined with it, which can only come from the soul” (1968, 198). Yet while there is a need for a soul in order to engage in what would rightly be called genuine language use, the ability to make sounds can be explained on entirely mechanistic grounds (the explanation being for Cordemoy very similar to how musical instruments produce sound). In this way sound production is like nutrition, circulation, and respiration, none of which, as Descartes had also believed, require a soul, but which result instead from a proper disposition of one’s organs. As for animals such as parrots which not only make sounds, but utter words, Cordemoy claims that ‘returning words’ is not a sign of a soul in such creatures, any more than a canyon’s echo requires rocks to have souls. As a testament to the significance of Cordemoy’s study of language, one scholar has written that Cordemoy “picked up one of Descartes’ arguments—based on the lack of true speech among animals—and developed it fully; so fully, in fact, that after Cordemoy the point was given very little attention, as if subsequent authors considered this the last word on the subject” (Rosenfield 1968, 40).