If (phenomenally) conscious AI systems are possible, then it is more plausible that AI systems will be welfare subjects. But how plausible is it that conscious AI systems are possible? The answer depends partly on whether there is a close link between consciousness and biology. The modest aim of this draft is to clarify what kind of link between consciousness and biology is crucial in this context. (I wrote the draft for an academic audience.)
The bottom line: what’s crucial for the possibility of AI consciousness is simply the biological requirement that to be conscious, a system needs to have biological states.
The biological requirement leaves open whether consciousness is itself biological, whether consciousness supervenes on anything biological, many questions about the biological correlates of consciousness, and whether consciousness has a functional basis. In my view, evidence for and against a close link between consciousness and biology that bears on the possibility of AI consciousness will tend to do so via the biological requirement. If that’s right, then the biological requirement is poised to serve as a crucial thesis, and we would do well to address it when attempting to bring biology to bear on the possibility of AI consciousness.
A priori, what is the motivation for elevating the very specific "biological requirment" hypothesis to the level of particular consideration? Why is it more plausible than than similarly prosaic claims like "consciousness requires systems operating between 30 and 50 degrees celsius" or "consciousness requires information to propegate through a system over timescales between 1 millisecond and 1000 milliseconds" or "consiousness requires a substrate located less than 10,000km away from the center of the earth"?
(I like the question and examples!)
I take motivations for the biological requirement and for considering it to be empirical rather than a priori.
One motivation for the biological requirement is that, in the cases we know about, fine-grained differences in consciousness seem to be systematically and directly underpinned by biological differences. This makes the biological requirement more plausible than many other claims at the same level of specificity.
While there isn’t a corresponding motivation for the temperature and timescale claims, there are related motivations: at least in humans, operating in those ranges is presumably required for the states that are known to systematically and directly vary with fine-grained differences in consciousness; going towards either end of the 30-50 C temperature range also seems to render us unconscious, which suggests that going outside the range would do so as well.
Looking beyond the human case, I take it that certain animals operating outside the 30-50 C range makes the temperature claim less plausible than the biological requirement. Admittedly, if we widen the temperature range enough, the resulting temperature claim will be as plausible as the biological requirement. But the resulting temperature claim’s plausibility will presumably be inherited from claims (such as the biological requirement) that are more informative (hence more worthy of consideration) with respect to which systems are conscious.
As for the distance claim, perhaps it would be plausible if one had Aristotelian cosmological beliefs! But I take it we now have good reason to think that the physical conditions that can exist on Earth can also exist far beyond it and that fundamental laws don’t single out Earth or other particulars for special treatment. Even before considering correlational evidence regarding consciousness, this suggests that we should find it implausible that consciousness depends on having a substrate within a certain distance from Earth’s center. Correlational evidence reinforces that implausibility: local physical conditions are strongly predictive of known conscious differences independently of appeal to distance from Earth’s center, and we don’t know of any predictive gains to be had by appealing to distance from Earth’s center. Another reason to doubt the distance claim is that it suggests a remarkable coincidence: the one planet around which that candidate requirement can be met just so happens to be a planet around which various other requirements for consciousness happen to be met, even though the latter requirements are met around only a small percentage of planets.
Setting aside plausibility differences, one reason to consider the biological requirement in particular is that it rules out AI consciousness, whereas the temperature, timescale, and distance claims are compatible with AI consciousness (though they do have important-if-true implications concerning which AI systems could be conscious).
All that said, I’m sympathetic with thinking that there are other candidate barriers to AI consciousness that are as well-motivated as the biological requirement but neglected. My motivation in writing the draft was, given that biology has been and will continue to be brought to bear on the possibility of AI consciousness, it should be brought to bear via the biological requirement rather than via even more specific and less crucial theses about biology and consciousness that are often discussed.