  All the same, the mind–body problem persists. In distinguishing the domain of the mental from that of the physical, Descartes struck a chord. Many philosophers accept the conceptual distinction, but remain uncertain of the underlying metaphysics: whether mind is identical with brain; or the mental emerges from complex processes in the brain; or constitutes a property that is different from any purely physical property, even while being instantiated by the brain. In this case, a problem that Descartes made prominent has lived far beyond his proposed solution.