Many philosophers seem to regard consciousness as lying outside the laws of physics, but top physicists seem to disagree.
David Deutsch, the Oxford physicist renowned for his pioneering work in quantum computation and constructor theory, offers a striking perspective on one of science’s most enduring mysteries. In a recent discussion about artificial general intelligence and the nature of consciousness, Deutsch presents a compelling materialist argument that consciousness emerges from computation—and that there’s nothing in fundamental physics preventing us from creating it artificially.
Deutsch begins by posing a thought-provoking question: “An intermediate step before considering AGI would be, is it possible to build a human being from scratch out of atoms? And I think that is clearly not forbidden by any fundamental theory that we have. Obviously, we’re nowhere near being able to do it.”
This opening gambit establishes his core thesis: consciousness isn’t some mystical property that transcends physical law, but rather an emergent phenomenon arising from the arrangement and interaction of matter. If we can theoretically reconstruct a human from constituent atoms—following the same physical laws that govern all matter—then consciousness must be substrate-independent.
Deutsch then tackles the subjective nature of experience head-on: “What is really operating to make the subjective sensation of falling and that kind of thing is not different between neurons and whatever your toy brain is made out of. If you could make the toy brain out of materials that did something analogous to the information processing in brains, then it would—I was about to say it would say that it experienced that as well, but I think it’s obvious that it would experience it.”
His reasoning hinges on a crucial insight about the nature of conscious experience itself: “When we say that we do experience it, we’re actually consulting our memory of experiencing it. We never experienced what’s actually happening in a particular instance. We only ever experienced what has happened to us one-fifth of a second or more ago. What’s more, we are interpreting it and all that is computations.”
This leads Deutsch to his ultimate conclusion, grounded in computational theory: “We know no machine can perform computations that are different from the ones that can be performed by a universal Turing machine or, if you like, a universal quantum computer. Although I very much doubt that the quantum computations are necessary for human consciousness.”
Deutsch’s argument directly challenges what philosopher David Chalmers famously termed the “hard problem of consciousness”—the question of how and why physical processes give rise to subjective experience. While Chalmers and other philosophers like Thomas Nagel argue that consciousness presents an explanatory gap that materialist science cannot bridge, Deutsch suggests this gap is illusory. From his perspective, once we understand that conscious experience is essentially the brain’s computational interpretation of stored information, the mystery dissolves.
This puts Deutsch squarely in the materialist camp alongside philosophers like Daniel Dennett and Patricia Churchland, who argue that consciousness will ultimately be explained through neuroscience and computation. However, his view contrasts sharply with property dualists like Chalmers, who accept that mental states arise from physical states but maintain that consciousness has irreducible subjective properties, and with substance dualists in the tradition of René Descartes, who posit consciousness as fundamentally non-physical.
The implications are profound: if Deutsch is correct, then artificial consciousness isn’t just theoretically possible but inevitable, limited only by our engineering capabilities rather than fundamental barriers in nature. In an age where artificial intelligence capabilities are advancing rapidly, his perspective suggests we may be closer to creating truly conscious machines than many realize—not through mystical emergence, but through the same computational processes that, he argues, generate human consciousness itself.