Here's one piece of practical reasoning: "If I do this then a person will reap some benefits and suffer some costs. On balance, the benefits outweigh the costs. So I ought to do it." Here's another: "If I do this then one person will reap some benefits and another will suffer some costs. On balance, the benefits to the one person outweigh the costs to the other. So I ought to do it." Many influential philosophers say that there is something (...) dubious about the second piece of reasoning. They say that it makes sense to trade-off costs and benefits within lives, but not across lives. In this paper I make a case for the second piece of reasoning. My case turns on the existence of morphing sequences—sequences of possible states of affairs across which people transform smoothly into other people. (shrink)

In the context of worlds with infinitely many bearers of utility, we argue that several collections of natural Utilitarian principles--principles which are certainly true in the classical finite Utilitarian context and which any Utilitarian would find appealing--are inconsistent.