Eric Schwitzgebel, a distinguished philosophy professor at the University of California, Riverside, has made a quiet but profound argument: consciousness almost certainly isn't locked inside biological flesh the way we once assumed it must be.
In a new working paper coauthored with Jeremy Pober, a former UCR graduate student now at the University of Lisbon, Schwitzgebel challenges what he calls "terrocentrism"—the unjustified belief that consciousness is unique to Earth-based organisms. The question matters now more than ever, as we build artificial intelligences of ever-greater complexity and contemplate the possibility of life elsewhere in the cosmos. If consciousness can arise in different forms, it reframes not just how we think about aliens and AI, but our entire understanding of what mind is.
The paper rests on a deceptively simple idea: substrate flexibility. A cup holds water whether it's made of glass or plastic; a song plays on vinyl or digital servers. Schwitzgebel and Pober argue that consciousness works the same way. It's not tied to any particular chemistry. The observable universe contains roughly 1 trillion galaxies, and astrobiologists have long hypothesized about life arising under radically different conditions—organisms with alternative amino acids, exotic solvents, even chemistries entirely foreign to Earth. In their paper, the philosophers estimate conservatively that at least 1,000 behaviorally sophisticated extraterrestrial civilizations have existed somewhere in the cosmos, though they note that one recent survey found median scientific estimates at one civilization per galaxy at some point in that galaxy's lifetime.
The authors don't claim such life definitely exists. Their point is more modest but more powerful: if life can emerge under vastly different chemical conditions, and if the universe provides an almost unimaginable number of opportunities for that emergence, then it would be surprising if every successful evolutionary path converged on Earth's particular building blocks. Evolution on Earth alone has produced minds that work in strikingly different ways. Octopuses, insects, and vertebrates process information through different neural architectures. Nature never settled on a single design here; why assume it did elsewhere?
This is where the Copernican principle enters. Nicolaus Copernicus and his successors delivered a series of humbling corrections: Earth isn't the center of the solar system, our solar system isn't the center of the galaxy, and the Milky Way isn't the center of the universe. Humanity occupies no special perch. Schwitzgebel and Pober extend this logic to consciousness itself. They coin the phrase "the Copernican principle of consciousness" to describe the idea that consciousness, too, is probably not exceptional to us.
The paper touches only briefly on artificial intelligence, and the authors themselves diverge on whether current AI could be conscious. But their arguments leave open that possibility—that someday, silicon or some other substrate might host genuine consciousness. They don't claim that every advanced life form must be conscious, only that if consciousness exists among behaviorally sophisticated beings, it would be strange to think only Earth organisms possess it. As Schwitzgebel puts it: "The universe may contain minds stranger than we can imagine." That strangeness isn't a barrier to consciousness. It might be its most likely expression.