To be sure, risks abound; but no one is proposing compassionate stewardship of ecosystems by philosophers. Humans are capable of choosing our own fut… - David Pearce

If we already lived in a cruelty-free world, the notion of re-introducing suffering, exploitation and creatures eating each other would seem not so much frightful as unimaginable – no more seriously conceivable than reverting to surgery without anaesthesia today.

[H]ere we come to the nub of the issue: the alleged moral force of the term "natural". If any creature, by its very nature, causes terrible suffering, albeit unwittingly, is it morally wrong to change that nature? If a civilised human were to come to believe s/he had been committing acts that caused grievous pain for no good reason, then s/he would stop - and want other moral agents to prevent the recurrence of such behaviour. May we assume that the same would be true of a lion, if the lion were morally and cognitively "uplifted" so as to understand the ramifications of what (s)he was doing? Or a house cat tormenting a mouse? Or indeed a human sociopath?

In the long run, there is nothing to stop intelligent agents from identifying the molecular signature of experience below hedonic zero and eliminating it altogether — even in insects. Nociception is vital; pain is optional. I tentatively predict that the world's last unpleasant experience in our forward light-cone will be a precisely datable event — perhaps some micro-pain in an obscure marine invertebrate a few centuries hence.