Batman v. Superman: The Dawn of Justice isn’t a great movie, but it does have one great teaching moment.  Batman is trying to get his hands on some Kryptonite.  Faithful butler Alfred wants to know why.  Batman’s rationale:

Batman: He [Superman] has the power to wipe out the entire human race, and if we believe there’s even a one percent chance that he is our enemy we have to take it as an absolute certainty… and we have to destroy him.

No one should be a utilitarian.  But from a utilitarian point of view, Batman’s logic is superficially appealing: He can sacrifice one life to save 7 billion humans with 1% probability, for a net expectational gain of 69,999,999 lives.  Until, of course, you pause and reflect.  Consider the following utilitarian counter-arguments, in ascending order of quality.

1. Out-of-pocket cost.  Destroying Superman will burn immense resources, and utilitarians have to take these into account.  But if you do the math, this is a pretty weak objection: Even if it costs \$7B – a hefty sum even for billionaire Bruce Wayne – standard value of life calculations say that’s worth 1000 lives, leaving a net benefit of 69,998,999 lives.

2. Opportunity cost. Superman doesn’t just have the power to destroy the world; he also has the power to save it.  If there’s a 1.1% chance that Superman will one day save the world if Batman lets him live, that amply justifies living with a 1% risk that he’ll one day destroy the the world.  And given the hazards of the DC Universe, the world is clearly safer with Superman than without him.

3. The self-fulfilling prophesy. Batman’s colossal error, though, is to fail to ask the question, “What would ever lead a superhuman as nice as Superman to destroy mankind?”  And the most credible answer is: “If mankind tries to destroy Superman first.”  Batman makes the classic hawk’s error: Failing to consider the possibility that he’s making enemies with his aggressive actions.  And when your putative enemy is Superman, that’s an error of cosmic proportions.  The common-sense strategy, rather, is to bend over backward to keep Superman on humanity’s side.