Ben, don’t get me wrong: I’m a materialist like you, and I agree that metaphysical idealism is incoherent nonsense (as Dr Johnson famously demonstrated). But this particular argument of yours is not a good refutation of it.

For the idealist, space itself doesn’t exist. Minds exist in some ethereal realm separate from space and time. The notion that a multiplicity of minds “presupposes different spatial coordinates” is unintelligible within the idealist framework.

Once again, I don’t accept Prudence Louise’s fundamental premises. But she is persuasive in saying that the existence of mind is not simply unexplained but intrinsically inexplicable, in principle, by materialist science. We can talk all we like about “emergent phenomena,” but Louise is right that it’s just a fig leaf over a genuine problem. Patterns of neuron firings in the brain are not the same thing as the smell of a rose.

What radical idealists like Louise fail to explain is the fragmenting of primordial consciousness-stuff into a multitude of individual minds—each bound to a particular (nonexistent!) material object, the brain and physical body—and the consistency of (nonexistent!) material reality between separate minds.

How is it that you and I agree that the (nonexistent!) table, room, and planet are as they are? Does the Great Cosmic Mind manipulate our individual experiences to maintain the illusion of coherent material reality? Why create individual minds in the first place? Or do they simply come about through some process or interaction within the noetic “stuff” itself? Are there laws or principles governing such interactions? If so, we’re back to science again.

So while I reject Louise’s answers, I agree with her that the consciousness problem is ultimately beyond the reach of science, just like the existential “something rather than nothing” question. I’m OK with that; there are things we are just destined never to know.