The real distinction between mind and body

Descartes's "conceivability argument" for substance-dualism is defended against Arnauld's criticism that, for all he knows, Descartes can conceive himself without a body only because he underestimates his true essence; one could suggest with equal plausibility that it is only for ignorance of his essential hairiness that Descartes can conceive himself as bald. Conceivability intuitions are defeasible but special reasons are required; a model for such defeat is offered, and various potential defeaters of Descartes's intuition are considered and rejected. At best though Descartes shows the separability of mind from body, not (as he claims) their actual separateness