A mind wrapped in skin and bone can feel like the obvious model for consciousness. But that assumption may say more about where you live than about what consciousness really requires.

In a new working paper, Eric Schwitzgebel of the University of California, Riverside, and Jeremy Pober, now at the University of Lisbon, argue that conscious experience probably does not depend on Earth-style biology alone. Their claim is not that every complicated system is conscious, or that today’s artificial intelligence has crossed that line. It is narrower and, in some ways, more unsettling: if consciousness is real, there is little reason to think it must be made only of flesh and blood.

The paper takes aim at what the authors see as an overly provincial view of the mind. On Earth, consciousness is associated with animal bodies, nervous systems, and specific biological chemistry. But the universe is vast, and life elsewhere, if it exists, may have been built under very different conditions.

“The universe may contain minds stranger than we can imagine,” Schwitzgebel said.

Rather than trying to settle the deeper mystery of what consciousness is, the two philosophers start from a simpler premise: consciousness exists, and at least some beings have it. From there, they ask what kinds of physical systems could support it.

Their answer turns on a concept called substrate flexibility. Some things, they note, can exist in many materials. A cup can be glass, metal, or plastic. A book can be paper or digital. In the same way, they argue, consciousness may be a property that can be realized in more than one kind of physical stuff.

That does not mean anything can host a mind. Granite, they assume, is out. They also do not argue that human consciousness could be copied perfectly into just any material. In fact, they grant a point made by critics of so-called neural replacement arguments: human experience may depend on fine biological details that are hard, or impossible, to duplicate exactly outside a living brain.

Still, they say, that is the wrong standard. The real issue is not whether silicon or some other medium can reproduce human consciousness in all its detail. It is whether consciousness as a broader phenomenon might emerge in systems organized very differently from us.

To get there, the paper builds a three-part argument. First, the authors say the universe likely contains at least 1,000 behaviorally sophisticated species across space and time. They call that estimate conservative. Astronomers estimate that the observable universe contains about 1 trillion galaxies, and some scientific surveys have placed the median estimate above one technological civilization per galaxy at some point in a galaxy’s lifetime.

Second, they argue those species would not all share Earth’s biochemical design. Astrobiologists have long explored whether life could emerge from different chemical ingredients, solvents, and environmental conditions. The paper points to work on alternative amino acids, alternative solvents such as ammonia and methane, and other unusual chemistries.

One vivid fictional example comes from Andy Weir’s novel Project Hail Mary, which imagines an alien with a mineral shell, mercury blood, steam-powered muscles, and a crystal brain, living in extreme heat and ammonia-rich air. Schwitzgebel and Pober do not present that as evidence. They use it as a reminder that once you stop assuming Earth is the template, biology can look a lot stranger.

Even on this planet, evolution has not settled on one design for intelligence. Octopuses, bees, dogs, and humans process the world differently. Nervous systems vary. Signaling systems vary. The authors argue that once those differences are obvious here, it becomes harder to insist that every conscious species in the universe must rely on the same basic biological recipe.

Their third step is philosophical. Schwitzgebel and Pober borrow from the Copernican tradition, the long series of scientific blows to the idea that Earth occupies a privileged place in the cosmos.

First Earth was removed from the center of the solar system. Then the solar system lost its central place in the galaxy. Then the Milky Way became just one galaxy among vast numbers. The lesson, they argue, is that people have repeatedly overestimated how special their position is.

They think consciousness may deserve the same correction.

If many behaviorally sophisticated species exist, and if they arise in very different forms, then it would be odd to say that only creatures with Earth-like biology can have inner experience. The authors call that assumption “terrocentrism,” a bias in favor of terrestrial life. Their alternative is what they name the Copernican principle of consciousness: among behaviorally sophisticated beings, humans should not assume they are uniquely privileged when it comes to conscious experience.

That does not mean every advanced species must be conscious. It does mean that treating Earth’s chemistry as the only possible home for consciousness starts to look like special pleading.

The argument naturally spills into debates about artificial intelligence, though the paper does not deliver a clean verdict there.

Pober takes the more cautious view. Just because consciousness may be possible in multiple substrates does not mean every substrate qualifies, and he sees no good reason to think current computer hardware supports conscious experience.

Schwitzgebel is more open to the possibility. Once you reject the idea that consciousness must be tied to human biology, he argues, it becomes harder to dismiss silicon-based systems just because they are made of silicon.

“It’s focused too much on whether silicon can duplicate a human brain and not enough on the broader question of what kinds of systems can be conscious,” he said.

That shift matters. A hummingbird, a bat, and an insect all fly, but not in the same way an eagle does. By analogy, consciousness elsewhere might not look much like human consciousness. It could vary with body plan, environment, signaling system, and chemistry.

The paper leaves that possibility open without claiming it has been realized in today’s machines.

If Schwitzgebel and Pober are right, the debate over consciousness needs a wider frame. Questions about alien life, animal minds, and artificial intelligence cannot be reduced to whether something looks enough like a human brain.

The more useful question may be whether very different physical systems can organize information, communication, coordination, and adaptive behavior in ways that support experience.

That does not prove any current AI is conscious, and it does not show that every complex organism or machine has an inner life. But it does push against a familiar assumption: that Earth’s biology sets the only terms on which consciousness can exist.

Research findings are available online in the working paper SchwitzPapers.