Renowned philosophers Erik Schwitzgebel from the University of California, Riverside, and Jeremy Pober, a postdoctoral researcher at the University of Lisbon, propose that consciousness is substrate flexible. This concept suggests that consciousness may not be limited to the biological tissues found on Earth, but could also emerge in entirely different physical materials throughout the universe.
Schwitzgebel and Pober discuss the potential for consciousness to exist in diverse physical substrates beyond Earth’s biology. Image credit: Fernando Rivas.
In their book, Professor Schwitzgebel and Dr. Pober state, “Who is conscious? We, the authors, and you, the reader, are conscious.” You can access their paper here.
“Some non-human animals likely share this trait. Further, we will explore the possibility that some extraterrestrial beings may also possess consciousness.”
“While we do not currently have evidence that today’s technology has produced conscious artifacts, we do not dismiss the potential for future discoveries.”
“Our argument emphasizes that consciousness can arise in a vast array of physical configurations, or substrates.”
Within the observable universe, there are approximately 1 trillion galaxies. While planets are abundant, most exist in environments vastly different from Earth.
The authors posit that at least 1,000 behaviorally sophisticated species capable of complex communication, goal-directed behavior, and cooperation likely exist somewhere in the universe.
They assert, based on astrobiological studies, that life on other planets could have evolved using distinct chemical building blocks, unlike the amino acids and nucleic acids fundamental to life on Earth.
Scientists have theorized about possible life forms in alien environments such as Venus, using sulfur compounds, organoborates, or silicon-based chemistry.
“We argue that it is improbable for all behaviorally advanced species in the universe to have evolved using the same substrate,” the researchers suggest in their paper.
“Even if our substrate is nearly optimal given known environmental constraints, a plethora of other substrates may be more advantageous in different environments.”
“For example, the extreme conditions of Venus’s gas clouds illustrate one such environmental limitation. Its atmosphere differs significantly from Earth’s, presenting unique challenges for life to thrive using alternative biochemical frameworks.”
The researchers further explore what they describe as the Copernican principle of consciousness.
Just as modern astronomy has debunked the notion that Earth occupies a special place in the cosmos, Schwitzgebel and Pober argue that we should not assume Earth holds a unique status in the realm of consciousness.
If multiple behaviorally sophisticated species evolved across various substrates in the universe, we cannot logically assert that only organisms sharing our biochemistry are capable of subjective experiences.
“It is an unsubstantiated view to presume that only entities with our specific biological makeup can be conscious,” they write.
“Consider that we might infer consciousness exists in all vertebrates and certain cephalopods and insects on Earth.”
“Assuming each galaxy contains, on average, a million planets, it is likely that species with comparable behavioral sophistication will emerge (even if technological civilizations are rare).”
The observable universe may have as many as 1 quintillion (1018) potentially habitable planets.
“With so many chances for life to arise, it’s inevitable that many of these life forms will appear quite unusual.”
“Thus, we shouldn’t confine the understanding of consciousness to organisms constructed from the same materials that form life on Earth.”
Professor Schwitzgebel and Dr. Pober also address the implications for artificial intelligence (AI).
However, they stop short of asserting that current AI systems possess consciousness.
In Dr. Pober’s perspective, we should refrain from assuming that today’s computer hardware is capable of supporting consciousness.
The potential for consciousness in different substrates does not automatically suggest that all substrates can achieve consciousness.
“Until we have compelling evidence to suggest otherwise, we should assume that current computer chips are incapable of consciousness,” he states.
“The default assumption is that substrates, such as those used in modern AI, do not exhibit consciousness unless there is valid reason to believe differently.”
Professor Schwitzgebel takes a slightly more optimistic stance regarding the potential for AI consciousness.
Once we dismiss the notion that consciousness strictly requires human biology, it becomes challenging to rule out silicon-based systems solely because of their composition.
Regardless, he argues that this aspect of the philosophical debate is too narrow.
“We should remain open to the possibility of AI consciousness,” he notes.
“When we recognize that consciousness does not depend on a specific substrate, it seems limiting to draw an arbitrary line, provided the substrate demonstrates the ability to support sufficient behavioral sophistication.”
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Jeremy Porber and Eric Schwitzgebel. 2026. Substrate flexibility and the Copernican principle of consciousness
Source: www.sci.news
