#population ethics

It implies that if everyone had lives of horrible torture, it would be an improvement to add a person whose life would be marginally less horrible torture, since that would increase average utility.

It also implies that whether it's right or wrong for us to create new lives could depend on aliens from Alpha Centauri who never interact with us. If these aliens live lives of extreme bliss, then every new life on Earth decreases world average utility, and we should all go extinct; and if their lives are extreme suffering, then it's okay to create horrible lives here, because that still increases the average.

For example, suppose you have a trillion rat brains on heroin that are experiencing an extremely positive level of utility. You could create a trillion-first brain, which would experience slightly less utility and also reduce the utility of the other brains, because there'd be less heroin to go around - but the new brain's utility would still be high enough to make up for the decrease, so total utility would be greater if you created it. But total utility would increase by less than the utility of the new brain, so by this theory, you shouldn't create it.

What losses were ours if we had not known birth?

Let living men to longer life aspire,

While fond affection binds their hearts to Earth,

But who hath never tasted life’s desire,

Unborn, impersonal, can feel no dearth.