Schwitzgebel and Pober: consciousness may not be specific to carbon

A study by Professor Eric Schwitzgebel of the University of California, Riverside, and Dr Jeremy Pober of the University of Lisbon, published in Philosophers' Imprint, puts a question from outer space into the debate on consciousness: if we met extraterrestrial beings that responded to their environment in complex ways, would it be reasonable to attribute consciousness to them?

"Substrate flexibility"#

The authors answer yes. Rejecting the assumption that consciousness depends on the carbon-based biology found on Earth, they argue that consciousness is substrate flexible: it could arise in very different physical forms capable of supporting enough complexity — for instance in chemical systems based on silicon or sulphur compounds.

The Copernican principle, applied to consciousness#

The study rests on what the authors call the Copernican Principle of Consciousness. Just as we accept that Earth holds no privileged position in the universe, it is unreasonable to assume that, among all beings displaying complex behaviour, only humans have conscious experience. Restricting consciousness to organisms with human-like biochemistry would be an unjustified terrestrial chauvinism.

Why robots are different#

Here the study draws an interesting line. On the authors' account, our attitude to a robot that appears conscious should differ from our attitude to a complex extraterrestrial being. If we know that a robot was designed to imitate consciousness, it is more reasonable to withhold judgement about whether it really is conscious. The alien being developed its complexity with no intention to imitate anything.

That distinction bears directly on the debate about attributing consciousness to AI systems.