No I don’t think we know if plants or insects feel pain. I would suspect that insects do, but my honest belief is that it is far less so than all animals and creatures with more developed senses. If I had to venture a guess they probably experience existence sorta like we do when we are very drunk
in the sense of just not having such an acute awareness of any thing at all. It certainly gets to the frontier of what we know about consciousness but I’m not sure I agree we know nothing about it, personal experience can tell us a lot. There’s clearly grades of it, and evidence suggests these
relate to more developed brains and sensors. Do I think killing masses of insects is bad then? I think when done to alleviate much more definite suffering by humans and animals it’s understood as a tradeoff with minimal moral hazard. But if you did this purely for fun, ya I think that’s sadism
Back to the classic example, people who pull apart even individual insects for fun, without any good scientific intention or who relish some sense of inflicted pain: I think everyone of normal morals recognizes this is wrong, and it’s because the pain tho slight is unalloyed by any tradeoff.
So when I think of eating meat, which is clearly a pleasure for me but not required to live or flourish, I understand it as something similar. We don’t have to kill cows, we do because it brings us joy not truly different from the kid pulling apart butterflies. I don’t want to be that anymore
Something occurred to me. In the classic example of someone taking a bug apart, does your mind go to an adult doing it? Or a kid? Like burning ants with a magnifying glass... That's something I associate with kids.