This is close to McNamara’s Confinement Problem, where he shows that under reasonable assumptions is morally acceptable to kill your mother. If there is an unlimited amount of utility, for example, if we can create a trust that grows over time and decide at a certain point to liquidate the trust and spend it on good works (this example is from Landesman) then there is unbounded utility. Therefore, for every world where we don’t kill our mother, there is a world with strictly high utility where we do - we just wait long enough for the growth of the trust to create enough utility to make up for our mother’s death.

What this shows is probably that infinite amounts of utility are non-intuitive.

McMichael says much the same thing:

“If there is a good which may exist in amounts of any size, then very horrible things turn out to be unconditionally permissible. Select any world w, however good. There is a world w’ which is better than w but in which Jesse gratuitously inflicts extreme pain on many kindly scholars. To be sure, there would have to be counterbalancing goods in w’, but I see nothing to prevent their appearance.”

Lewis’s response to this was that utilitarianism was dumb. Technically, he said “not a commonsensical view.”