Researchers at the University of California, Riverside and the University of Lisbon have proposed a bold new argument in a 2026 working paper: consciousness may be able to arise in physical systems far different from the carbon-based biology found on Earth. Their claim reaches across philosophy, astrobiology and artificial intelligence, asking whether minds could exist in bodies made from unfamiliar chemistry or future machines designed along strange lines.
Eric Schwitzgebel, a distinguished professor of philosophy at the University of California, Riverside and Jeremy Pober, a former UCR graduate student now at the University of Lisbon, call the central idea substrate flexibility. In plain terms, they argue that conscious experience may depend on the right kind of complex organization rather than one exact recipe of earthly flesh, nerves and cells.
The paper arrives at a moment when the search for life beyond Earth is widening and artificial intelligence is raising harder questions about mind-like behavior. Schwitzgebel and Pober treat consciousness as a real phenomenon, then ask how much the material basis of that phenomenon can vary. Their answer leaves room for possibilities that sound almost alien by design.
A Copernican shift for consciousness
The researchers draw inspiration from one of science’s most famous humbling lessons. The Copernican tradition moved Earth away from the center of the cosmic picture. Earth became one planet around one star in one galaxy among many. Schwitzgebel and Pober extend that style of reasoning to the mind.
Their proposed Copernican principle of consciousness says that humans should avoid treating Earthly biology as uniquely privileged without strong reason. Among behaviorally sophisticated beings, they argue, human minds may occupy a less special place than instinct suggests. The idea fits a long scientific pattern: the universe keeps turning out to be larger, older and more varied than familiar experience implies.
In this framing, consciousness becomes a cosmic question as well as a biological one. If the universe contains many sophisticated life forms and if those life forms evolved under different chemical and physical conditions, then a narrow Earth-only view of consciousness would need serious support. Schwitzgebel and Pober argue that such support remains limited.
The authors use the term “terrocentrism” for the tendency to place Earth life at the center of the discussion. Their point is cautious but provocative. A conscious animal on Earth gives humanity one confirmed example. That single example may be a poor guide to every possible mind in the universe.
Why materials may be flexible
The key concept is substrate flexibility. A property is substrate flexible when it can appear in more than one kind of material. A cup can be glass, metal, ceramic, or plastic. A book can exist as bound paper or a digital file. A song can be stored on vinyl, a compact disc, or a computer drive.
Schwitzgebel and Pober ask whether consciousness might work in a similar way. Their working paper states the claim directly: “Consciousness is substrate flexible.” The phrase comes from the paper’s abstract and captures the argument in its shortest form.
The researchers avoid claiming that every material can support experience. Flexibility still has limits. A paper book and an e-book can both carry a story, but sand scattered on a beach usually cannot. In the same way, consciousness may require certain structures, processes, or forms of organization that only some physical systems can provide.
That distinction matters for the debate. Substrate flexibility allows consciousness to be tied to physical reality while remaining open to many possible physical forms. A mind could depend on matter, energy, memory, feedback and behavior without depending on human neurons in every detail.
“The universe may contain minds stranger than we can imagine,” Schwitzgebel said. The line captures the paper’s central mood: serious caution paired with an unusually wide sense of possibility.
Alien life as a test case
The strongest setting for the argument is alien life. The observable universe contains vast numbers of galaxies, stars and planets. Astronomers have shown that planets are common and many worlds likely differ sharply from Earth in temperature, atmosphere, pressure and chemistry.
Schwitzgebel and Pober estimate that at least 1,000 behaviorally sophisticated extraterrestrial civilizations have existed somewhere in the cosmos. They describe that number as conservative in the context of scientific estimates about civilizations across galactic lifetimes. The point is a probability argument, rather than a report of detected aliens.
Astrobiologists have explored possible life chemistries beyond the familiar carbon-water model. Researchers have considered alternative amino acids, different solvents and other chemical frameworks. Schwitzgebel and Pober build on that wider imagination. If life can evolve under many conditions, complex behavior may also arise from many kinds of material organization.
Science fiction offers a useful picture here because it helps readers imagine biological difference. The UCR discussion mentions the alien in Andy Weir’s “Project Hail Mary,” with a rock-like exterior, mercury blood, steam-powered muscles and a crystal brain. The example is fictional, yet it illustrates the kind of unfamiliar embodiment that the philosophical argument takes seriously.
The authors are making a limited claim. Alien consciousness has yet to be observed. Still, if sophisticated extraterrestrial life exists in many forms, it would be surprising if every conscious lineage required the same biochemical ingredients that produced mammals, birds, insects and cephalopods on Earth.
Earth’s many nervous systems
Life on Earth already shows that intelligence and behavior can be built in many ways. Dogs, bees, octopuses, birds and humans all process information through biological systems, yet their bodies and nervous systems differ greatly. Nature has generated many designs for sensing, acting, learning and responding.
Octopuses are especially useful examples because much of their nervous system is distributed through their arms. Bees navigate, communicate and solve problems with tiny brains. Dogs inhabit a world rich with scent, social cues and learned routines. These creatures share Earth’s broad biochemistry, but they demonstrate that mental capacities can emerge from very different animal architectures.
Schwitzgebel and Pober use this diversity as a stepping-stone. If Earth alone contains many routes to complex behavior, the broader universe may contain far more. Alien evolution could produce systems that process information through chemistry, tissues, mineral structures, or other media that human science has barely imagined.
This does not mean every sophisticated behavior proves consciousness. Behavior can be hard to interpret, especially in unfamiliar organisms. The paper’s claim is more measured. It argues that there is little reason to assume consciousness must always use the exact materials and arrangements found in Earth animals.
That approach also changes how scientists and philosophers might frame the search for life. A future alien organism could challenge familiar categories. Its senses might operate in ranges humans cannot feel. Its memory might have a physical basis unlike a brain. Its experience, if present, could be deeply unlike human experience.
What this means for AI
Artificial intelligence inevitably enters the discussion because AI systems already produce behavior that looks increasingly sophisticated. Schwitzgebel and Pober address AI briefly and their views differ. Both treat the issue as open, with special caution around present-day systems.
Jeremy Pober urges restraint about current computer hardware. The fact that consciousness may occur in more than one substrate does not imply that every substrate can support it. In that view, today’s chips may lack the right physical features or organization for conscious experience.
Eric Schwitzgebel is somewhat more open to future possibilities. If consciousness can arise outside Earth-like biology, silicon-based systems become harder to exclude simply because they are silicon-based. The deeper question becomes what kinds of organization, behavior and causal structure are enough.
Schwitzgebel summarized one concern about the debate by saying, “It’s focused too much on whether silicon can duplicate a human brain.” The comment points to a shift in focus. Instead of asking whether a machine can copy human consciousness exactly, researchers can ask whether different kinds of conscious systems are possible.
The paper compares this issue to flight. An eagle’s flight is highly specific, with feathers, muscles, bones and a living body. Flight in a broader sense appears in bats, insects, birds and aircraft. Consciousness may have a similarly broad category, with human consciousness as one version rather than the template for every possible case.
The limits of the claim
The argument remains philosophical and speculative. Schwitzgebel and Pober offer a working paper, rather than a laboratory discovery of alien minds or conscious machines. Their case depends on probability, analogy, astrobiological possibility and a Copernican style of reasoning.
That caution is important. Human consciousness is the clearest case we know from the inside. Many animals likely have forms of experience, yet drawing exact boundaries is difficult even on Earth. The problem becomes much harder when applied to alien organisms or artificial systems that may behave in unfamiliar ways.
The authors also separate humanlike consciousness from consciousness in general. Human consciousness may require many details of human biology, including our nervous system, senses, bodily needs and evolutionary history. Consciousness as a broader category could include forms of experience with different structures and contents.
This distinction helps keep the claim precise. The paper does not need future aliens or AI systems to feel exactly as humans feel. It only needs consciousness to be possible in some substantially different substrates. A strange mind could be conscious while having experiences that humans struggle to describe.
The result is a wider scientific and philosophical target. If Schwitzgebel and Pober are right, the search for minds should look beyond familiar biology. Consciousness may be one more feature of the universe that becomes larger once humanity stops using Earth as the measure of all things.
