Is "can they feel pain" or "can they feel pleasure" really the right question, though? Let's say we research the biological correlates of pleasure until we understand how to make a compact and efficient network of neurons that constantly experiences maximum pleasure. Because we've thrown out nearly everything else a brain does, this has the potential for orders of magnitude more sentience per gram of neurons than anything currently existing. A group of altruists intend to create a "happy neuron farm" of these: are they awesome and inspiring or misguided and creating nothing of value?
I think this is a false dilemma. I don't find that scenario "awesome", but I do believe it would be creating something of value. The reason I believe this is that, when I experience intense pleasure, I can apprehend that these experiences ought to exist in the universe, by virtue of how they feel like. Filling the universe (or a portion of it) with these experiences is therefore a great thing, regardless of how "awesome" or "inspiring" I happen to find it.
I've edited the post to just ask the simpler question of whether this is valuable.
In the recent discussions here about the value of animals several people have argued that what matters is "sentience", or the ability to feel. This goes back to at least Bentham with "The question is not, Can they reason? nor, Can they talk? but, Can they suffer?"
Is "can they feel pain" or "can they feel pleasure" really the right question, though? Let's say we research the biological correlates of pleasure until we understand how to make a compact and efficient network of neurons that constantly experiences maximum pleasure. Because we've thrown out nearly everything else a brain does, this has the potential for orders of magnitude more sentience per gram of neurons than anything currently existing. A group of altruists intend to create a "happy neuron farm" of these: is this valuable? How valuable?
(Or say a supervillian is creating a "sad neuron farm". How important is it that we stop them? Does it matter at all?)