“Suppose we who are living now decide to ignore global warming, with the result that the lives of future people are much harder. It would seem that we have made things worse for those future people. But, in fact, as long as their lives are worth living this is not the case—because if we had acted differently, the world would have been different, and those particular people would never have existed (in the same way that if cars had not been invented most people alive today would never have been born). So, although we have made the world worse in the future, we have made life worse for no one. Parfit calls this conundrum the Non-Identity Problem. He believes that it makes no difference: we still have just as much reason to avoid making life worse for people in the future. But he worries—rightly, as it turns out—that other people may draw the opposite conclusion: since global warming will not make particular future people worse off, it may seem less bad.”

— Larissa MacFarquhar, How to be Good (The New Yorker, September 5, 2011)