New research explores substrate flexibility for consciousness beyond Earth

Scientists have raised the possibility that consciousness does not depend exclusively on human-like biological structures.

Eric Schwitzgebel, a philosophy professor at the University of California, Riverside, and Jeremy Pober, a postdoctoral researcher at the University of Lisbon, argue that conscious experience could develop in systems composed of materials very different from those of Earth’s carbon-based life.

Starting from the premise that consciousness is a genuine phenomenon, the researchers question whether it must be linked to Earth-specific biology or if it could manifest in unfamiliar forms elsewhere.

Their study appears amid growing debates about conscious artificial intelligence, though Schwitzgebel and Pober only briefly discuss AI and do not reach a consensus on its potential consciousness. Their analysis leaves open the possibility that AI might become conscious in the future, despite current systems likely lacking it.

Concept of Substrate Flexibility

The core concept introduced is “substrate flexibility,” which describes properties that can be realized through multiple kinds of materials. For example, a cup can be made from glass or plastic, and music can be stored on vinyl or digital formats.

Applying this idea to consciousness, the authors suggest it might similarly arise from various physical substrates.

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

Estimating Extraterrestrial Civilizations

Considering the vastness of the observable universe, which contains about one trillion galaxies, astronomers believe planets are widespread, many with environments unlike Earth’s.

Schwitzgebel and Pober estimate that at least 1,000 behaviorally sophisticated extraterrestrial civilizations have existed somewhere in the cosmos, describing this as a conservative figure. They reference a recent survey indicating a median scientific estimate of over one civilization per galaxy at some point in that galaxy’s history.

Astrobiologists have explored the possibility of life forms built from alternative chemical structures, such as different amino acids or solvents.

In fictional science grounded in plausible science, author Andy Weir’s “Project Hail Mary” depicts an alien with a shell of oxidized minerals, mercury blood, and a crystal brain, originating from a hot planet with an ammonia-rich atmosphere.

While Schwitzgebel and Pober do not claim such exotic life definitely exists, they argue that if life can emerge under varied chemical conditions and the universe offers many opportunities for life to develop, it would be surprising if every evolutionary lineage used the same biochemical components.

They also highlight the diversity of nervous systems on Earth, noting that octopuses, bees, and dogs process information differently, indicating multiple biological designs exist even here.

The Copernican Principle Applied to Consciousness

Their argument draws on the Copernican tradition, which progressively displaced Earth and humanity from a central cosmic position.

They propose a “Copernican principle of consciousness,” suggesting it is unlikely that consciousness is uniquely tied to Earth-like organisms. Assuming otherwise would be a form of “terrocentrism,” meaning unjustified privileging of Earth life.

They clarify they are not claiming every advanced life form must be conscious, but that it would be unusual if only organisms with Earth’s biochemical makeup could possess consciousness.

Historically, humans have repeatedly discovered they are less central and unique than previously believed, and Schwitzgebel and Pober suggest consciousness might follow this pattern.

Implications for Artificial Intelligence

The paper raises questions about AI consciousness but does not argue that current AI systems are conscious.

Pober cautions against assuming that present computer hardware can support consciousness, noting that substrate flexibility does not imply consciousness can arise in every substrate.

Schwitzgebel is more receptive to the idea that silicon-based systems might be conscious, since consciousness may not require human biology.

He criticizes the philosophical focus on whether silicon can replicate the human brain, advocating for broader inquiry into what kinds of systems can be conscious.

The authors distinguish between specific properties tied to human consciousness and the broader category of consciousness itself. They compare this to flight, which exists in various forms among hummingbirds, bats, and insects, though none fly identically.

They propose that consciousness may similarly appear in diverse forms without closely resembling human consciousness.

Reference: “Substrate Flexibility and the Copernican Principle of Consciousness” by Jeremy Pober and Eric Schwitzgebel, 28 May 2026.