 In the initial book of the Recherche, on the senses, Malebranche proposes that the erroneous belief in the Aristotelians as well as in Augustine that sensible qualities exist in bodies has its source in a misuse of “natural judgments” that help in the conservation of the human body. Here he is following Descartes’ account in “Meditation VI” of the “teachings of nature,” and in particular the claim there that the purpose of sensations is not to teach us about the nature of bodies but simply to inform us of what is beneficial or harmful to the human composite. Just as Descartes had urged that erroneous beliefs about the nature of body can be avoided by attending to the clear and distinct perceptions of the intellect, so Malebranche counseles that we avoid error by attending to what the clear idea of matter reveals to us about the nature of body. As we have seen, Malebranche has Augustinian reasons for saying that the idea that so instructs us exists in God. By his own admission, however, the conclusion that the idea that instructs us is an idea of extension derives from the recent discoveries of Descartes.