UtilitarianismJohn Stuart Mill

Mill's Utilitarianism is short, polemical, and deceptively simple. Its thesis is that actions are right in proportion as they tend to promote happiness and wrong as they tend to produce the reverse. Happiness is pleasure and the absence of pain. This is the Greatest Happiness Principle, and Mill spends five chapters defending it against objections he knows are coming.

The most consequential move is the distinction between higher and lower pleasures. Against Bentham, who treated all pleasures as commensurable, Mill insists that the pleasures of intellect, feeling, and moral sentiment are superior in kind to those of mere sensation. The competent judge, someone who has experienced both, invariably prefers the higher. "It is better to be Socrates dissatisfied than a fool satisfied."

Chapter III addresses the sanctions of the principle: what motivates people to act for the general happiness? External sanctions (law, opinion) matter, but the real force is internal, a feeling of duty rooted in the social nature of human beings. Chapter IV offers the controversial "proof" of the principle: each person desires their own happiness; therefore the general happiness is desirable. Critics have called this a fallacy; Mill would reply that ultimate ends admit of no proof in the strict sense, only of considerations capable of determining the intellect.

Chapter V reconciles utility with justice. Justice is not a separate principle but the name for the most important class of utility rules, those protecting individual rights and security, the conditions without which no happiness is possible.