A few centuries from now, if involuntary suffering still exists in the world, the explanation for its persistence won't be that we've run out of comp… - 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.

... our descendants may recognize that we are the sociopathic emotional primitives in the grip of an affective psychosis. Jealousy, envy, resentment, ridicule, hate, anger, disgust, spite, contempt, schadenfreude and a whole gamut of nameless but mean-spirited states we undergo each day are a toxic legacy of our Darwinian past. More commonly, perhaps, our genetic make-up ensures we simply feel indifference to the plight of all but a handful of significant others in our lives. Right now, for instance, one knows dimly at some level that there is frightful and preventable suffering in the world. Yet most of us feel no overpowering moral urgency to do anything about it.

Humans already massively intervene in Nature, whether through habitat destruction, captive breeding programs for big cats, "rewilding", etc. So the question is not whether humans should "interfere", but rather what ethical principles should govern our interventions.