A philosopher argued every moral claim ever made is false

J.L. Mackie's error theory holds that when people say 'cruelty is wrong,' they mean to describe an objective fact about the universe — but no such facts exist. So every moral judgment anyone has sincerely made is systematically mistaken, Mackie argued, even though morality still functions as a useful human practice.

— J.L. Mackie, Ethics: Inventing Right and Wrong — 1977
Go deeper: get the book →