In John Stuart Mill's "Utilitarianism", the main theories are greatest happiness principle and hedonism (pleasure is the only intrinsic good). Utilitarianism sticks to believe the theory of human nature that is pursuing happiness and avoiding suffering. They insist happiness is the final objective in our lives and everyone in the society has the right to pursue their own happiness.
Mill points out that people would consider both of the qualities and quantities factors at the same time when we criticize something, but it is ridiculous if only pay attention on the quantities factor when we judge and weigh the happiness (Chapter 2). Therefore, Mill divides the pleasure into lower and higher parts. The higher pleasures come from art achievement, virtue, intelligence, emotion and moral sentiments aspects. On the contrary, lower pleasures are merely sensual such as sexual desire and material fulfillment. The previous one is more valuable for people to seek. .
Moreover, there may be no people want to be lower animals in order to enjoy the pleasure of animals; no smart persons want to be a fool; no educated people are willing to be ignorant and no good persons want to be mean or selfish (Chapter 2). Mill emphasizes the importance of education, and described that people who lack of education are easy to satisfied with the lower pleasure but people who own more senses or quality need more things in order to feel pleasure. Mill also presents that "it is better to be a human being dissatisfied than a pig satisfied; better to be Socrates dissatisfied than a fool satisfied (Chapter 2). Do not like Bentham who only emphasizes on the quantity of hedonism, Mill pays more attention on the quality of the hedonism which increase the ethical value of the utilitarianism and heighten the practical value.
In addition, Mill believes in any situation, the morally right action is the one that makes everyone affected the happiest.