Utilitarians
A morality one could do arithmetic on. By the late eighteenth century the old foundations of right and wrong, divine command and natural law, were losing their grip on a Britain busy reforming its laws and filling its factories, and the question underneath every reform was blunt: by what standard. Bentham answered with one measurable thing. The right act is whatever produces the greatest happiness, happiness meaning pleasure and the absence of pain, counted across everyone it touches, each person counting for one. No rights the senses cannot find, no commands from on high, no mysteries: just a sum, and a program for rewriting the law to come out higher. Mill, raised inside the system, spent his life rescuing it from the charge that it was fit only for pigs, building in pleasures of a higher kind, individual liberty, and rights worth protecting. Sidgwick made it rigorous. And then the standard objections arrived, the ones that still define the argument: that a pure sum could license sacrificing one innocent person to please a crowd, and that asking each act to maximize the world's happiness asks more than any human can give. The tradition is the long attempt to keep the clean, countable core while answering for what counting alone leaves out.
