Philosophers are seriously exploring a provocative question: Does consciousness need a physical body? This inquiry is highlighted in a new paper by Eric Schwitzgebel, a philosophy professor at the University of California, Riverside, and his former student Jeremy Pober.
Their research suggests that consciousness might emerge in forms of life that are fundamentally different from humans. For example, they envision life forms similar to the rock-skinned, crystal-brained alien from the film Project Hail Mary. While they do not define consciousness or assert that alien minds exist, they focus on whether consciousness must be linked to Earth’s specific biology.
Their argument is built on the concept of "substrate flexibility." This means that certain properties can be achieved with various materials. Just as a cup can be made of glass or plastic and still hold water, consciousness may also be realizable through different physical structures.
Given the vastness of the universe, which houses approximately a trillion galaxies, the researchers estimate that at least a thousand sophisticated civilisations could have developed throughout cosmic history. It seems unlikely that all successful life forms would have identical biochemical makeups, especially when conditions vary greatly.
Schwitzgebel and Pober reference the Copernican principle, which suggests humanity is not the centre of the universe. They argue that assuming consciousness is limited to beings like ourselves reflects an unjustified belief in human uniqueness.
The discussion also touches on artificial intelligence (AI). Pober cautions that substrate flexibility does not guarantee that all materials, like silicon, can support consciousness. Schwitzgebel, however, believes that dismissing silicon solely due to its composition is increasingly hard to justify. Ultimately, they aim to uncover what kinds of systems can actually become conscious.
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