Probably not, according to Eric Schwitzgebel, distinguished professor of philosophy at the University of California, Riverside.
in a new work paperSchwitzgebel and Jeremy Pober, a former UCR graduate student who is now a postdoctoral researcher at the University of Lisbon, argue that conscious beings may be possible even if they are built from materials very different from those found in life on Earth. One example comes from the recent blockbuster “Project Hail Mary,” which features a five-limbed alien with a rock-like exterior.
Rather than attempting to define consciousness itself, researchers start with the assumption that consciousness is a real, recognizable phenomenon. His focus is on a more concrete question: does consciousness have to depend on Earth-style biology?
The article comes at a time when debates about conscious artificial intelligence are becoming more common. While the authors briefly address AI, they do not take a shared position on whether current systems are conscious. In fact, they disagree with each other on some aspects of the issue. Still, his broader argument leaves open the possibility that consciousness could one day emerge in AI, even if current systems do not possess it.
The idea of ”substrate flexibility”
A central concept of the article is what philosophers call “substrate flexibility.”
The idea is simple. Some properties can exist in many different materials. A mug, for example, may be made of glass, plastic, metal, or other substances. A book can exist as printed pages or as a digital file. Likewise, records can be stored on vinyl or compact discs.
Schwitzgebel and Pober maintain that consciousness also belongs to this category.
In his view, consciousness is not necessarily tied to a single physical substance.
“The universe may contain stranger minds than we can imagine,” Schwitzgebel said.
Extraterrestrial life can take many forms
Astronomers estimate that the observable universe contains approximately 1 trillion galaxies. Planets appear to be abundant and most likely have environments that differ dramatically from Earth’s.
For their argument, Schwitzgebel and Pober estimate that at least 1,000 extraterrestrial civilizations with sophisticated behaviors have existed somewhere in the universe. They describe this figure as conservative and point to research that suggests the median scientific estimate is greater than one civilization per galaxy at some point during a galaxy’s lifetime.
Meanwhile, astrobiologists have explored the possibility that life elsewhere could be built from different materials than life on Earth. Researchers have considered alternative amino acids, alternative solvents, and even completely different chemical structures.
Andy Weir’s novel “Project Hail Mary” offers a vivid fictional example. In the book, readers encounter an alien species with a shell made of oxidized minerals, blood made of mercury, two circulatory systems, muscles powered by steam, and a crystal brain. The creature comes from an extremely hot world with an atmosphere saturated with ammonia.
Philosophers do not affirm that such exotic life definitively exists. Instead, they argue that if life can arise under a wide range of chemical conditions, and if the universe offers countless opportunities for life to develop, it would be surprising if each successful evolutionary pathway arrived at exactly the same biological ingredients.
The Earth itself offers evidence of nature’s creativity. Octopuses, bees and dogs process information differently. Even on our own planet, evolution has produced a wide variety of nervous systems rather than a single model. According to the authors, the rest of the universe may present even greater diversity.
The Copernican principle of consciousness
The authors’ main argument is inspired by the Copernican astronomical tradition.
Over time, discoveries associated with Nicholas Copernicus and later astronomers revealed that the Earth is not the center of the solar system, the solar system is not the center of the galaxy, and the Milky Way is not the center of the universe. Humanity has repeatedly learned that its place in the cosmos is less special than once believed.
Schwitzgebel and Pober suggest that conscience may deserve the same treatment.
If there are many behaviorally sophisticated species throughout the universe and they possess very different biological structures, then assuming that consciousness belongs only to organisms like us would reflect what the authors call “terrocentrism”: an unwarranted treatment of life on Earth as uniquely privileged. They refer to this broader idea as the “Copernican principle of conscience.”
The researchers do not maintain that all advanced species must be conscious. Instead, they maintain that if consciousness occurs among beings with sophisticated behaviors, it would be strange to conclude that only organisms with a biology similar to ours could experience it.
History has repeatedly shown that humans are not as unique or central as we once assumed.
The same lesson can be applied to conscience. Rather than being a rare characteristic restricted to a specific type of biological organism, consciousness could arise whenever evolution – or something like it – generates the right level of complexity.
What about artificial intelligence?
Naturally, the article raises questions about AI, but the authors stop short of claiming that current AI systems are conscious.
Pober argues that the possibility of multiple conscious substrates does not mean that all substrates can support consciousness. In his opinion, there is no reason to assume that current computing hardware gives rise to conscious experience.
Schwitzgebel is somewhat more receptive to this possibility. He argues that once we reject the idea that consciousness requires human biology, it becomes harder to dismiss silicon-based systems simply because they are made of silicon rather than organic tissue.
More generally, Schwitzgebel believes the debate has focused on the wrong question.
“There is too much focus on whether silicon can duplicate a human brain and not enough on the broader question of what types of systems can be conscious,” he said.
The article distinguishes between highly specific properties and broader categories. Asking whether human consciousness can reproduce on a different substrate is a very specific question because human consciousness can depend on many details of human biology. Consciousness as a general phenomenon is a broader concept.
The authors compare this distinction to flight. Asking whether another creature can replicate an eagle’s exact style of flight is different from asking whether flight itself can occur in other ways. Hummingbirds, bats, and insects fly, but they do it in different ways.
Similarly, consciousness can take many forms throughout the universe without necessarily resembling human consciousness.
Does consciousness depend on flesh and blood?
The answer is almost certainly no, according to Eric Schwitzgebel, distinguished professor of philosophy at the University of California, Riverside.