A Quick Argument for Objective Morality

Here’s a quick deductive argument for moral objectivism, where by moral truths being “objective” I mean that they hold independently of human opinion.

The Argument

1. It is morally wrong for a man to torture an infant just for fun.
2. It would remain morally wrong to torture an infant just for fun even if a baby torturer thought otherwise and killed everyone who disagreed with him.
3. If (1) and (2) are true, then objective morality exists.
4. Therefore, objective morality exists.

Justification for (3): in the scenario depicted in (2) it’s morally wrong for a man to torture infants just for fun even though all human opinion thinks otherwise (since the torturer killed off everyone who disagrees with him), in which case the moral truth “It’s morally wrong for a man to torture infants just for fun” would be holding despite human opinion, in which case it seems we have an example of an objective moral truth (i.e. holding true independently of human opinion) thereby giving us objective morality.

You could deny premise (1). Do you believe there’s nothing morally wrong with torturing infants just for fun?

You could bite the bullet and deny premise (2), say it’s not morally wrong for a man to torture infants just for fun as long as he believes otherwise and kills everyone who disagrees with him. Do you think that’s a reasonable belief?

Why I Like It

I think this is a good deductive argument for moral objectivism because it quickly reveals how intellectually pricey it is to deny objective morality. It’s not reasonable to believe that there’s nothing morally wrong with torturing infants just for fun, so premise (1) is not plausibly false. Likewise, it’s not reasonable to believe that it’s not morally wrong for a man to torture infants just for fun as long as he believes otherwise and kills everyone who disagrees with him; so premise (2) is not plausibly false.

This forces the disbeliever of moral objectivism in a very intellectually uncomfortable position, especially in a debate, because even if the disbeliever is willing to bite a bullet and reject a premise, most people won’t find the disbeliever’s premise rejection tenable.