Incoherent. The only thing that drives a belief in Util, as a good friend of mine once said is: "Happiness is good, asking why happiness is good is like asking why 2+2 = 4, it just is!". That's a raw intitutive assertion, one that people can simply disagree with. Most of the virtues of utilitarianism can be captured by other systems that don't rely on happiness being good, and the ones that do not rely entirely on this assertion.
Incoherent. The only thing that drives a belief in Util, as a good friend of mine once said is: "Happiness is good, asking why happiness is good is like asking why 2+2 = 4, it just is!". That's a raw intitutive assertion, one that people can simply disagree with. Most of the virtues of utilitarianism can be captured by other systems that don't rely on happiness being good, and the ones that do not rely entirely on this assertion.