Probably not, says Eric Schwitzgebel, a distinguished philosophy professor at the University of California, Riverside.
In a new research paper, Schwitzgebel and Jeremy Pober, a former UCR graduate student and now a postdoctoral researcher at the University of Lisbon, argue that conscious beings could exist even if they were made of materials very different from life on Earth. One example of this can be found in the recent blockbuster “Project Hail Mary.” The film features a five-limbed alien with a rock-like appearance.
Rather than attempting to define consciousness itself, researchers begin with the assumption that consciousness is a real, recognizable phenomenon. Their focus is on narrower questions. That is, does consciousness need to depend on terrestrial biology?
The paper arrives at a time when discussions about conscious artificial intelligence are becoming increasingly common. Although the authors briefly mention AI, they do not agree on whether current systems are conscious. In fact, they disagree with each other on some aspects of this issue. Still, their broader argument leaves open the possibility that AI may someday become conscious, even if today’s systems are not.
Concept of “substrate flexibility”
The central concept of this paper is what philosophers call “substrate flexibility.”
The idea is simple. Some properties may be present in different materials. For example, a cup can be made from glass, plastic, metal, or other materials. Books can exist as printed pages or as digital files. Similarly, records can be stored on vinyl discs or compact discs.
Schwitzgebel and Porber argue that consciousness also belongs to this category.
In their view, consciousness is not necessarily tied to a single physical substance.
“There may be stranger minds in the universe than we imagine,” Schwitzgebel said.
Alien life may take many forms
Astronomers estimate that the observable universe contains approximately 1 trillion galaxies. Although the planet appears to be rich in Earths, it is likely to have an environment very different from Earth.
In their argument, Schwitzgebel and Pober estimate that at least 1,000 behaviorally sophisticated extraterrestrial civilizations exist somewhere in the universe. They describe this number as conservative and point to research that suggests the median scientific estimate is greater than one civilization per galaxy at some point in a galaxy’s lifetime.
Meanwhile, astrobiologists have been studying the possibility that life elsewhere is built from materials different from life on Earth. Researchers have considered alternative amino acids, alternative solvents, and even completely different chemical structures.
Andy Weir’s novel “Project Hail Mary” provides a vivid fictional example. In this book, readers encounter an alien species with a shell made of oxidized minerals, mercurial blood, two circulatory systems, steam-powered muscles, and a crystal brain. This creature came from a very hot world with an atmosphere saturated with ammonia.
Philosophers are not claiming that such exotic life definitely exists. Instead, they argue that if life can emerge under a wide range of chemical conditions, and the universe provides countless opportunities for the growth of life, it would be surprising if all successful evolutionary pathways arrived at exactly the same biological components.
The earth itself shows evidence of nature’s creativity. Octopuses, bees, and dogs all process information differently. Even on our planet, evolution has produced a wide variety of nervous systems, rather than a single blueprint. The rest of the universe may exhibit even greater diversity, the authors say.
Copernican principle of consciousness
The authors’ main argument draws inspiration from the Copernican tradition in astronomy.
Over time, discoveries associated with Nicolaus Copernicus and subsequent 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 learned over and over again that our place in the universe is not as special as once believed.
Schwitzgebel and Porber suggest that consciousness may also deserve the same treatment.
Given that many behaviorally sophisticated species exist throughout the universe and have vastly different biological structures, assuming that consciousness belongs only to organisms like us would reflect what the authors call “telocentrism,” or the unfair treatment of life on Earth as having special privileges. They call this broader concept the “Copernican principle of consciousness.”
The researchers are not arguing that all evolved species must be conscious. Rather, they argue that if consciousness arises among behaviorally sophisticated beings, it is strange to conclude that only creatures with biology similar to ours can experience it.
History has repeatedly shown us that humans are not as unique or central as we once assumed.
The same lesson may apply to consciousness. Consciousness is not a rare feature confined to a particular type of organism, but can emerge whenever evolution, or something like it, creates an appropriate level of complexity.
What about artificial intelligence?
While the paper naturally raises questions about AI, the authors stop short of claiming that current AI systems are conscious.
Porber argues that the possibility of multiple substrates of consciousness does not mean that all substrates can support consciousness. In his view, there is no reason to think that today’s computer hardware produces conscious experience.
Schwitzgebel is somewhat open to that possibility. Once we reject the idea that human biology is necessary for consciousness, he argues, it becomes difficult to ignore silicon-based systems simply because they are made of silicon rather than organic tissue.
More broadly, Schwitzgebel believes the debate is focusing on the wrong issues.
“There’s been too much focus on whether silicon can replicate the human brain, and not enough on the broader question of what kinds of systems can have consciousness,” he said.
This paper distinguishes between highly specific properties and broader categories. Asking whether human consciousness can be recreated on different substrates is a very specific question, since human consciousness may depend on many details of human biology. Consciousness as a general phenomenon is a broader concept.
The author likens this distinction to flight. Asking whether another creature can reproduce the eagle’s exact flight style is different from asking whether flight itself can occur in other forms. Hummingbirds, bats, and insects all fly, but they fly in different ways.
Similarly, consciousness can take many different forms throughout the universe and does not necessarily resemble human consciousness.
Does consciousness depend on living humans?
The answer is almost certainly no, says Eric Schwitzgebel, a distinguished professor of philosophy at the University of California, Riverside.
