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

Genes and culture have co-evolved. But crudely, natural selection "designed" male human primates to hunt nonhumans and build coalitions of other male human primates in order to wage territorial wars of aggression. Nature didn't design us to become a scientific community and collaborate to overcome aging. It's difficult to imagine that any human enemy could inflict such gruesome damage on the victims as growing old. The ravages of aging strike down combatants and civilians alike. So the trillions of dollars that humans currently spend on ways to harm and kill each other ("defence") would be more fruitfully spent on defeating our common enemy. We should work together to build a "Triple S" civilisation of superlongevity, superhappiness and superintelligence.

[O]ne might naively suppose that a negative utilitarian would welcome human extinction. But only (trans)humans - or our potential superintelligent successors - are technically capable of phasing out the cruelties of the rest of the living world on Earth. And only (trans)humans - or rather our potential superintelligent successors - are technically capable of assuming stewardship of our entire Hubble volume.

Suffering exists only because it was good for our genes. Conditionally-activated negative emotions were fitness-enhancing in the ancestral environment. In the current era, apologists for mental pain are serving as the innocent mouthpieces of the nasty bits of code which spawned them.