“We only know the intrinsic character of events elsewhere. They may be just like the events that happen to us, or they may be totally different in strictly unimaginable ways. All that physics gives us is certain equations giving abstract properties of their changes. But as to what it is that changes, and what it changes from and to – as to this, physics is silent.”
To say that color, sound, taste, etc, as common sense understands these things, is not a property of material objects (but only exist in our minds), and that all there really is to matter is what physics tells us about it, is to (implicitly) reject materialism.
The reason is fairly simple: To say that matter doesn’t actually have these other properties (that scientists set aside when doing experiments) is just another way of saying that these properties are immaterial. Once one has done that, one is committed to some kind of cartesian dualism (whether one likes it or not).
This is for the very simple fact that science doesn’t operate without the sensations of the mind that materialists dismiss as not being part of matter. Theories, or any kind of explanation, cannot exist without reference to these properties. If one is going to say that these aren’t part of matter, then say that nothing more than matter exists, one dismisses science.
The only way to dismiss the cartesianism that materialists passionately mock is to find a way of saying that these extra traits, which are ignored by physics, are actually properties of matter after all.
Of course, many materialists think they have this answer in neuroscience. They seem to think that science will one day explain how these ideas arise from the brain. Personally, I’m convinced that neuroscience will one day explain much about the causal processes in the brain. But it simply cannot explain things that, as a science, it is forbidden to take into account.
Which is exactly where this started. And we can’t solve a problem using the same method that created the problem in the first place. Science (neuroscience as much as any other) ignores qualia (sensations as common sense understands them). It can record what brain-processes tend to be associated with people claiming (verbal behavior) to experience particular qualia. It cannot describe them. It leaves that to writers and other artists.
But there is always the option that Russell suggests: putting these extra things back into our concept of matter, and to quit demanding that the picture of reality given to us by physics is exhaustive.
After all, that demand is philosophical, not scientific. No scientific test on it has ever been (or could ever be) done on it. Those who demand that scientific evidence should be required before forming a belief should definitely reject this claim that there are no properties of matter other than what physics studies.
The trouble with this is that it means the abandonment of materialism. Once one is willing to accept that the properties of matter revealed by experience offer us information about the physical not offered by science (and, indeed, which science depends on), one is moving back toward a premodern view of the world–and all the arguments for theism that go with it. But that is the only way to believe in matter without believing in a cartesian view of the soul.
In general, passionate materialists respond to this argument as they do to many others: by appealing to the unknown. Who knows what the answer is, but they are “okay with not knowing”, and apparently are confident that the answer will be a better fit with materialism than the alternatives.
Personally, I don’t see a logical difference between being okay with not knowing, in this sense, and appealing to magic. But, on a more personal level, this makes a certain amount of sense. All roads before us, if one follows the path of logic, lead to theism.
The only way to maintain one’s atheism, in this case, is to stand at the intellectual crossroads and be “okay with not knowing”.