When I wrote about whether one could balance 10 lives against 1, John had a very interesting point in the comments about the viewpoint that sentient life is special and therefore superior to other forms of life / nonliving environments — and he felt pretty strongly that it was a BAD idea to believe this was true. I want to speak a bit more about the role of sentience in my head.
Why is sentient life special? Well, I believe it is because it is different from everything else. That is, a person who can think and choose is different from an automaton, and also different from an animal. Right away, if you believe humans are NOT different from automatons / animals (e.g. there is no free will or agency, and humans are just biomachines), we differ in fundamental assumptions. John said in his comment that he thinks humans are another step on the evolutionary ladder – something to which I agree but which I also think doesn’t tell the whole story. I have a hard time comparing sentience (self-awareness and free-willedness) to a hypothetical other quality; I suppose there could be an equivalent alien quality that deserves special treatment to sentience but is not itself sentience, but I can’t imagine it.
(My friend Will also commented on Facebook about how he believes sentience is a spectrum, to which I also mostly agree – I just define a “sentient being” along that spectrum past a point that is not arbitrary; it corresponds to being free-willed and “sufficiently” self-aware, which is of course the point of contention!)
Just being different is not really good enough to talk about superiority – but there is another question to which the answer might give weight to the “superiority of sentience”: in what way is sentient life different than other life in its capabilities and actions? The more sentient an entity is, the more organized and capable of self-organization it is, and the more capable it is of willfully fighting entropy and the tendency of the universe toward disorder. I think this is a worthy ideal – fighting against entropy. In doing so, we create amazing experiences and things and shape the universe for the better. Yes, sentient beings are also even MORE capable of destruction, but that’s to be balanced against their greater capability for creation.
I don’t advocate letting humanity (or any other sentient race) using up the environment or other nonsentient species for their own benefit, but I do in some sense subscribe to a “greater good” theory that is sentient-centric. If anyone is capable of understanding their own impact on others, it’s a sentient lifeform – and therefore it is for sentient lifeforms to judge each other on their impact and by the ideals they work toward together.