 In Third Meditation, Descartes initially defines material falsity as something that “occurs in ideas, when they represent non-things as things” (7:43). He offers as an example the idea of cold: our senses represent cold as a positive quality of objects, but Descartes considers the possibility that cold itself is merely the absence of heat, and so isn't a quality of its own. Accordingly, this case should be assimilated to sensory misrepresentation: representing things as they are not (representing cold as a quality when it is the absence of a quality). Material falsity would be a matter of misrepresentation.