I see no reason why any life form could not feel pain. I have never understood where this idea comes from that certain animals don’t. I mean, I guess humans want to believe that creatures that don’t look like us can’t act like us… it makes us feel special, better, somehow higher than them. But when we start assuming things because we want them to be true, or in order to excuse our actions, then we have to start questioning those assumptions.
If you’ve ever watched ants or other insects, or played with them as a child, you’ll know that they will recoil from certain things. Does it mean anything to distinguish between the words “discomfort” or “pain” or “dislike” or “fear” or “distaste” in such examples? Because if deciding that the ant is experiencing pain or fear is just a matter of the degree of discomfort, I think that argument is already lost.
Who can deny that our mammalian pets have emotions? It is absurd to think that they don’t. Perhaps insects and fish experience discomfort in ways that are different than ours – does it matter whether we call this emotion? If so, why?
For the record, I am a meat-eater, although I would prefer that butchering be done in ways that prevent suffering. I will step on an ant or swat a fly in my house, but I prefer to shoo spiders out the door. I don’t feel guilt about any of it, and I don’t need to pretend that they don’t feel pain in order to justify that.