McRae on Innate Ideas: A Rejoinder

Extract

It will come as no surprise that I have a different interpretation of the four passages in which, McRae claims, Descartes “definitely includes extension and its modes in what is given through the senses”. In the first, Descartes includes extension, etc., among his ideas of corporeal bodies. This is not to say that he includes them among his adventitious ideas, though. All adventitious ideas are ideas of external bodies. But the converse is not true. Not all ideas of corporeal bodies are ipso facto adventitious ideas, for, as I see it, the idea of the true and immutable nature of body is non-sensible and innate. McRae slides from “all adventitious ideas seem to be ideas of external bodies” to “all ideas of external bodies (including extension) are adventitious”.