The Argument
- It is morally wrong for a man to torture an infant just for fun.
- 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.
- If (1) and (2) are true, then objective morality exists.
- Therefore, objective morality exists.
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.