I would draw the boundary at sentience, because there is no moral disagreement about the intrinsic badness of (undeserved) pain. That we are currently uncertain about where exactly sentience begins in the animal kingdom does not constitute an objection to the moral argument; nor is that empirical uncertainty relevant in this context, since no reasonable person would deny that pigs, cows and sheep are all sentient beings.
If that’s what you think about the concept of sentience, fine; I can restate my reply without using that concept. I would draw the boundary at the ability to experience the sensation of “liking”, as that term is operationally defined by Kent Berridge.
I would draw the boundary at sentience, because there is no moral disagreement about the intrinsic badness of (undeserved) pain. That we are currently uncertain about where exactly sentience begins in the animal kingdom does not constitute an objection to the moral argument; nor is that empirical uncertainty relevant in this context, since no reasonable person would deny that pigs, cows and sheep are all sentient beings.
We may be actually more uncertain about what sentience is rather than where it begins. It could belong to the “free will” category of concepts.
If that’s what you think about the concept of sentience, fine; I can restate my reply without using that concept. I would draw the boundary at the ability to experience the sensation of “liking”, as that term is operationally defined by Kent Berridge.