 Such a reading is sensitive not only to Descartes’ Sixth Meditation comments but also to his further remarks on real distinction in Fourth Replies. There Descartes says that for “establishing a real distinction it is sufficient that two things can be understood as ‘complete’ and that each one can be understood apart from the other” (AT 7:221, CSM 2:156). A thing is complete, for Descartes, when it is a substance: