utilitarian
Singer challenges this by arguing that formerly unequal rights for gays, women, and certain races were justified using the same set of intuitions. Posner replies that equality in civil rights did not occur because of ethical arguments, but because facts mounted that there were no morally significant differences between humans based on race, sex, or sexual orientation that would support inequality. If and when similar facts emerge about humans and animals, the differences in rights will erode too. But facts will drive equality, not ethical arguments that run contrary to instinct, he argues. Posner calls his approach "soft utilitarianism", in contrast to Singer's "hard utilitarianism". He argues:
