Materialism and dark matter
Theoretical physicist Sean Carroll, on immateriality in the material world:
In fact, most of the particles in the standard model don’t play a role in your everyday life…you don’t need a lot of the ingredients of the standard model to explain you. You are made up of up quarks, down quarks, and electrons, held together by the strong nuclear force and electromagnetism…it doesn’t require that much. We know… [the dark matter particle] doesn’t interact with you and your body. How do we know that? Because there are rules for what happens when one particle interacts with another, and if a certain particle could interact with the things you are made of, the electrons and protons and neutrons, then we would be able to make it.
Carroll is slightly overstating his case here, because as far as we can tell dark matter does seem to interact with our bodies. If you look at the night sky, for example, you will see the effects of dark matter holding our galaxy together; gravity alone cannot explain why the stars of the Milky Way galaxy cluster into a pinwheel instead of spinning out in all directions. This is dark matter exercising a direct influence on the photons that hit the photochemical receptors in your eye. And this is just a known effect of dark matter; for all we know, it is also doing all kinds of other things to our body that we simply do not yet understand.
Still, the point Carroll is making is worth reflecting on. When we think of the material world, we have historically thought of a giant machine with gears turning each other, or of a space of atoms bouncing off of each other like lotto ping pong balls, or (more recently) of a kind of cloudy quantum matrix of fields that influence each other. We have thought, in other words, of things that are material that interact.
To put it another way, interaction is something that the material world does, not something that it is. The grammar of our use suggests that elements of the material world are material whether they happen to interact with each other or not. But this raises the unusual possibility that Carroll touches on: that there are elements of the material universe that do not actually interact with the rest of it.
What do I mean by this? Let’s distinguish between two different claims:
The weak claim: There are things in this universe that cannot interact with other things in any way that we can ever discern. Consider for example so-called local hidden-variable theory — the idea that quantum behavior is not indeterminate, but is in fact determined by particles or forces that, because they are smaller than Planck’s constant, can never be observed. Such particles and forces would certainly be material in any meaningful sense of the word; they would “exist” in precisely the same way that atoms exist, and that you exist, and they would produce effects in our universe in the same way that other material phenomena do. But these are ontological claims; as a point of epistemology, we will never be able to trace these effects back to their causes. So from the perspective of the natural sciences, we will never be able to say that these are truly “interacting” with the rest of the world in any falsifiable way: they could be, but we will never be able to prove it.
The strong claim: There are things in this universe that have properties which seem to qualify them as “material,” but which cannot actually interact with the other material elements universe. Perhaps we might be able to logically infer their existence even though we have no empiricial proof that they exist, in much the same way as Dmitri Mendeleev inferred the existence of Germanium 17 years before it was actually discovered. Or perhaps we will not even be able to logically infer their existence, but they nevertheless exist in some material sense.
Much of this, of course, turns on what we actually mean by “material.”
Historically, again, talk about the material world was often talk about things like atoms or elements — about substances, or what today we would call “matter.” Today however we often recognize as part of the “material” world things that are not matter at all, like gravity. Einstein demonstrated that matter and energy appear to be in some sense interchangeable, and today quantum physics suggests that what we call “matter” is better understood as a property of a kind of abstract field. John Wheeler, meanwhile, goes even further and argues that quantum physics is bringing us towards a universe defined not by substances or matter, but by information: “every physical quantity, every it, derives its ultimate significance from bits, binary yes-or-no indications”.
One way to respond to this scientific trajectory would simply be to declare that “materialism” has been debunked: the word had clear connotations of substance and matter in the past that do not actually appear to describe the universe in which we live. As Chomsky put it in a lecture on Newton, we can’t talk about a relationship between quantum information and the material world because “that’s like saying what’s the relation between information and ectoplasm; you can’t ask that question till you tell us what ectoplasm is and nobody can tell us what material is.”
Another response, however, would simply be to look for the line of continuity between our old conception of the universe-as-material and our new conception of the universe-as-information. From that perspective, you can insist that the material hypothesis has held insofar as it always revolved around ideas of supervience, for example — the notion that there is some kind of ultimate underlying substrate to the universe which defines what it is. From this perspective, “material reality” is something like the pixels that define a computer screen, and the universe is just the picture that we perceive from various configurations of these pixels. From this view it does not much matter what the pixels are made of; what matters is the informational role they play in displaying certain colors and not others.
It seems to me that any salvageable notion of “materialism” has to make this kind of move, but notice what this evolved concept does not bring with it. Nothing about our TV metaphor requires that the things it seems to display on screen need interact in any meaningful way. Supervience, the property of materialism that we think still works, simply implies that the universe reflects its informational subtrate. Imagine an algorithmic process that creates everything we as human can interact with in the universe — the up quarks, the down quarks, the electrons, and so on — but that also creates all kinds of other things with which they simply do not interact. We would not recognize them as “material” in the old discredited sense, but we would have to in the modern sense of the term.
***
This discussion may seem a bit far afield from my usual writing on Marxism, but its implications for Marxist thought are profound and direct. Much of Marxist thought, after all, relies on making a hard distinction between the material world and the immaterial world, and insists that our political and analysis must focus on the former while rejecting the latter. In particular, Marxism often takes aim at liberalism’s conception of ideas as the engine of historical and political change, insisting that it is really the material world that drives change, and even drives the evolution of ideas.
A simplistic but common reading of Marx’s materialism understands this claim from a perspective most analagous to 17th century mechanism: everything, even ideas, can be explained through contact-physics style interactions between matter. In this analysis, it is thus illegitimate to talk about the world in any other way. Concepts like a marketplace of ideas and spiritual forces are obviously ruled out by this naive materialism — but so are concepts like Carroll’s dark matter, which would have to be dismissed as unscientific. And indeed, one often encounters this sort of thinking in certain threads of Soviet scientific thought; see for example the Soviet critique of “psychologism.”
Marx, one must add, did not actually see the world this way. Recall, in Capital, his aspiration “to lay bare the economic laws of motion of modern society.” This was a direct reference to Newton, whose laws of motion served as a definitive rejection of mechanism; what Newton proved is that there were forces in our universe like gravity that were not “material” in the sense of having substance, but that nevertheless had effects on material things.
In his reference to “economic laws of motion,” Marx is insisting that materialism cannot be reduced to an essentially mechanical description of matter. The universe behaves in certain ways that can only be understood informationally, by positing abstract “laws” that it seems to obey, and the task of materialism is to uncover those laws in a way that accurately describes the world around us. Sadly, for those who want Marxism to be an obscure catalogue of arcane metaphysical doctrines, Marx’s “materialism” mostly just devolved into a call for scientific rigor. And if that leads us to strange conclusions like the notion of “material” objects that do not even interact with each other, so be it.
Refer enough friends to this site and you can read paywalled content for free!
And if you liked this post, why not share it?