Suppose that Metropolis is in grave danger of being totally destroyed, say by a meteorite careening down toward it from space. For whatever reason, Superman refuses to save it. I am in a position credibly to tell him: “You son of a bitch! Either you save the city or I’ll kill Lois Lane.” Am I justified / permitted / required to do that?
For natural morality, we must assume that I do not love the citizens of Metropolis with any special love as myself. It is admitted, however, that I may prefer the city spared so that society and the free market are not damaged and production is not curtailed, which would make me, as a participant in the economy, somewhat poorer.
Natural deontology forbids me to coerce Superman, because I am not allowed to commit an injustice for any personal gain.
Natural utilitarianism enjoins me not to make things worse, but it does not command me to make them better. Therefore, I am not required to bring about the great good of the salvation of Metropolis. I am permitted to walk away with indifference. I am not responsible for the threat to the city, and I am not anyone’s keeper.
Deontology then prohibits coercing Superman, and consequentialism does not require me to coerce him. On the whole, coercion is not permitted, and I ought to let the city perish.
Christian deontology similarly forbids unjust coercion, such as threatening an innocent girl with death, in fact even more stringently, since we contrast with hatred not benign indifference but love.
But Christian utilitarianism now bids me to create good, to improve the world, and in particular to avert great evils. Saving Metropolis certainly qualifies as a huge work of mercy. I am now morally required to force the reluctant Superman to act.
The two approaches seriously conflict with each other. To resolve the conflict, we may invoke threshold deontology. Again, it seems to me that each person needs to establish his own personal thresholds upon some serious reflection and soul-searching and then act accordingly with single-minded confidence. In this case, for me, the greater good brought about is high above the threshold for coercing Superman. Consequentialism takes over, and on the whole, Christian morality compels me to threaten Lois Lane.