“This suggests that consciousness … is the hardware that the software described by physics runs on.”

Is Matter Conscious? Why the central problem in neuroscience is mirrored in physics.—Hedda Hassel Mørch, Nautilus

The nature of consciousness seems to be unique among scientific puzzles. Not only do neuroscientists have no fundamental explanation for how it arises from physical states of the brain, we are not even sure whether we ever will. Astronomers wonder what dark matter is, geologists seek the origins of life, and biologists try to understand cancer—all difficult problems, of course, yet at least we have some idea of how to go about investigating them and rough conceptions of what their solutions could look like. Our first-person experience, on the other hand, lies beyond the traditional methods of science. Following the philosopher David Chalmers, we call it the hard problem of consciousness.

But perhaps consciousness is not uniquely troublesome. Going back to Gottfried Leibniz and Immanuel Kant, philosophers of science have struggled with a lesser known, but equally hard, problem of matter. What is physical matter in and of itself, behind the mathematical structure described by physics? This problem, too, seems to lie beyond the traditional methods of science, because all we can observe is what matter does, not what it is in itself—the “software” of the universe but not its ultimate “hardware.” On the surface, these problems seem entirely separate. But a closer look reveals that they might be deeply connected.

Might the hard problem of consciousness and the hard problem of matter be connected? There is already a tradition for connecting problems in physics with the problem of consciousness, namely in the area of quantum theories of consciousness. Such theories are sometimes disparaged as fallaciously inferring that because quantum physics and consciousness are both mysterious, together they will somehow be less so. The idea of a connection between the hard problem of consciousness and the hard problem of matter could be criticized on the same grounds. Yet a closer look reveals that these two problems are complementary in a much deeper and more determinate way. One of the first philosophers to notice the connection was Leibniz all the way back in the late 17th century, but the precise modern version of the idea is due to Bertrand Russell. Recently, contemporary philosophers including Chalmers and Strawson have rediscovered it. It goes like this.

This suggests that consciousness—of some primitive and rudimentary form—is the hardware that the software described by physics runs on. The physical world can be conceived of as a structure of conscious experiences. Our own richly textured experiences implement the physical relations that make up our brains. Some simple, elementary forms of experiences implement the relations that make up fundamental particles. Take an electron, for example. What an electron does is to attract, repel, and otherwise relate to other entities in accordance with fundamental physical equations. What performs this behavior, we might think, is simply a stream of tiny electron experiences. Electrons and other particles can be thought of as mental beings with physical powers; as streams of experience in physical relations to other streams of experience.

This idea sounds strange, even mystical, but it comes out of a careful line of thought about the limitations of science. Leibniz and Russell were determined scientific rationalists—as evidenced by their own immortal contributions to physics, logic, and mathematics—but equally deeply committed to the reality and uniqueness of consciousness. They concluded that in order to give both phenomena their proper due, a radical change of thinking is required.

And a radical change it truly is. Philosophers and neuroscientists often assume that consciousness is like software, whereas the brain is like hardware. This suggestion turns this completely around. When we look at what physics tells us about the brain, we actually just find software—purely a set of relations—all the way down. And consciousness is in fact more like hardware, because of its distinctly qualitative, non-structural properties. For this reason, conscious experiences are just the kind of things that physical structure could be the structure of.