Why Do We Owe Anything to People Who Do Not Yet Exist?

Imagine two energy policies. One is cheaper now but leaves toxic waste requiring supervision for centuries; the other costs more but carries less long-term risk. Policy changes jobs, migration and who meets whom, so decades later different people may be born. Someone living with the consequences of the first policy may therefore be unable to say, “Had the other policy been chosen, I would have been better off.” Under that history, they might never have existed.

Derek Parfit's non-identity problem exposes the difficulty. If an action counts as harmful only when it makes the same person worse off than an alternative would have, many plainly troubling long-term choices appear to leave nobody with a complaint. That does not mean future people lack moral standing. John Rawls's account of justice between generations, along with later sufficientarian approaches, asks how institutions should preserve basic conditions and fair opportunities for those who come later.

My view is that responsibility need not wait until a victim can be named. We exercise power now, while future people cannot participate in today's decision. Where severe and foreseeable burdens can be avoided at reasonable cost, uncertainty about identity should not excuse imposing them. This does not require reducing every future risk to zero. It requires open comparison of uncertainty, cost and irreversible consequences, without treating “different people would have existed” as a moral exemption.

https://plato.stanford.edu/entries/justice-intergenerational/