Mill was one of the most rock-and-roll guys of the nineteenth century. He learned to speak ancient Greek before he was three years old. By the time he was eight, he was reading the old geometers in Latin. He was a brilliant logician and economist by his teens. To call him a very great genius is a huge understatement.
Mill’s father, who was somewhat famous himself, had put him through a brutal education. Not surprisingly, Mill had a nervous breakdown when he left home. Mill recovered, though, and became a women’s-lib and antislavery writer, an eminent philosopher, political thinker, Member of Parliament, and cultivator of third-degree sideburns. He married his lifelong sweetheart when he was 45, after she had finally divorced her deadbeat first husband.
Like Kant, Mill is trying to come up with a single rule of ethics. Mill, though, is a consequentialist. He believes that consequences matter and intentions do not. Like Epicurus and Aristotle, Mill is a hedonist. All three believe that humans do (or should) strive for happiness. Unlike the Greeks, though, Mill believes that we should try to make everyone happy, not just ourselves. Good actions, then, are those that create the most happiness for the most people—that, in a nutshell, is his whole philosophy, called “utilitarianism”
Utilitarianism has been enormously influential, not least because it is so easy to sum up. It provides a philosophical foundation for law, democracy, and economics that still pervades western life.