Full Idea
Clearly no explanation can be given by these substantial forms for any natural action, since their defenders admit that they are occult and that they do not understand them themselves, ...so they explain nothing.
Gist of Idea
Substantial forms are not understood, and explain nothing
Source
René Descartes (Letters to Regius [1642], 1642.01), quoted by David S. Oderberg - Real Essentialism 267 n5
Book Reference
Oderberg,David S.: 'Real Essentialism' [Routledge 2009], p.267
A Reaction
[Oderberg gives refs for attack by Locke and Hume, p.66] Descartes' target is Aristotle's hylomorphism. The problem seems to be understanding what Aristotle meant, which is much more than mere 'shape'. More like 'controlling principle'.