Worth pondering ...

It is instructive to see what has happened in the thought of that wonderful old man, Lord Russell. In his youth he was the leader of the extreme realists, holding that every quality of physical things, including one’s own body, existed independently of its being experienced. In his last important work, Human Knowledge: Its Scope and Limits, he comes round to the view that everything we immediately experience lies in the realm of consciousness. The body is not now a solid object among others in public space, but a boiling mass of unobserved and unobservable particles in a space of their own. And the mind is not a set of shadowy processes, but the whole “choir of heaven and furniture of earth” that forms one’s experienced world.

Russell the ancient sage is nearer the truth, I think, than Russell the bright young man. And if so, the place of consciousness in the scientific scheme of things is transformed. For consciousness is then no longer a tenuous shadow whose very existence is doubtful, but our base and starting point, the region of greatest certainty, while the realm of the physical becomes a twilight zone of inference, of hypotheses about the invisible and impalpable, of flights of metaphysical speculation. Matter has become, says Russell with a dash of his pleasant hyperbole, “a wave of probability undulating in nothingness.” No one knows much about it; Bohr’s model of the atom was outdated a decade or two later. Meanwhile both the values and the certainties of life, which lie in the sphere of consciousness, are much the same as they were thousands of years ago.

- from "The Limits of Naturalism" by Brand Blanshard (Hat tip, Dave Lull, responding to a question I had put in an email: "Why do we decide that the only way to validate consciousness is by material means? Seems to me it ought to be the other way around." .)