Asklemmy

I don't mean to say that neural activity ∝moral weight. I am merely asserting that something without neural activity at all (or similar construct) can't be worth anything. This is why a rock has no moral value, and I don't need to treat a rock nicely.

I am less confident -- but still fairly confident -- that consciousness, pain, and so on require at least a couple neurons -- how many, I'm not sure -- but creatures like tiny snails and worms probably aren't worth consideration, or if they are then only very little. Shrimp are complex enough that I cannot say for sure that they aren't equal in value to a human, but my intuition says they still don't have fully-fledged sentience; I could be wrong though.

The strongest evidence that shrimp don't have sentience is anthropic -- if there are trillions of times more shrimp than humans, why am I a human and not a shrimp? Isn't that astoundingly improbable? But anthropic arguments are questionable at best.