  Let \(\{U(t)\}\) be an infinite well-being stream, that is, \(\{U(t)\} = (U(0),U(1),\ldots ,U(t),\ldots)\).  We say \(V(\{U(t)\})\) is continuous if in an appropriate mathematical sense the values of \(V\) for well-being streams \(\{U(t)\}\) that don’t differ much in the space of \(\{U(t)\}\)s are close to one another. A further condition on the \(V\)-function that is ethically attractive is “monotonicity”. To define the notion let us say a well-being stream is “superior” to another if no generation enjoys less well-being along the former than along the latter and if there is at least one generation that enjoys greater well-being in the former than it does in the latter. We say that \(V\) is monotonic if \(V\) is larger for a well-being stream than it is for another if the former is superior to the latter.