Suppose I publicly endorse a moral theory which implies that the more headaches someone has, the better the world becomes. Suppose someone asks me to explain my rationale for claiming that a world that contains more headaches is better. Suppose I reply by saying, “Because in this world, more people suffer headaches.”
Because it doesn’t contain anyone else. There’s only one human left and they’re “suffering horribly”.
Suppose I publicly endorse a moral theory which implies that the more headaches someone has, the better the world becomes. Suppose someone asks me to explain my rationale for claiming that a world that contains more headaches is better. Suppose I reply by saying, “Because in this world, more people suffer headaches.”
What would you conclude about my sanity?
Most people value humanity’s continued existence.