The basic idea behind hedonistic thought is that pleasure is the only thing that is good for a person. This is often used as a justification for evaluating actions in terms of how much pleasure and how little pain (i.e. suffering) they produce. In very simple terms, a hedonist strives to maximize this net pleasure (pleasure minus pain). The nineteenth-century British philosophers John Stuart Mill and Jeremy Bentham defended the ethical theory of utilitarianism, according to which we should perform whichever action maximizes the aggregate good. Conjoining hedonism, as a view as to what is good for people, to utilitarianism has the result that all action should be directed toward achieving the greatest total amount of happiness. Though consistent in their pursuit of happiness, Bentham and Mill’s versions of hedonism differ. There are two somewhat basic schools of thought on hedonism:[1]
  • One school, grouped around Jeremy Bentham, defends a quantitative approach. Bentham believed that the value of a pleasure could be quantitatively understood. Essentially, he believed the value of a pleasure to be its intensity multiplied by its duration - so it was not just the number of pleasures, but their intensity and how long they lasted that must be taken into account.
  • Other proponents, like John Stuart Mill, argue a qualitative approach. Mill believed that there can be different levels of pleasure - higher quality pleasure is better than lower quality pleasure. Mill also argues that simpler beings (he often references pigs) have an easier access to the simpler pleasures; since they do not see other aspects of life, they can simply indulge in their lower pleasures. The more elaborate beings tend to spend more thought on other matters and hence lessen the time for simple pleasure. It is therefore more difficult for them to indulge in such "simple pleasures" in the same manner.

Critics of the quantitative approach assert that, generally, "pleasures" do not necessarily share common traits besides the fact that they can be seen as "pleasurable."[citation needed] Critics of the qualitative approach argue that whether one pleasure is higher than another depends on factors other than how pleasurable it is.[citation needed] For example, the pleasure of sadism is a more base pleasure because it is morally unpalatable, and not because it is lacking in pleasure.

In the medical sciences, the inability to derive pleasure from experiences that are typically considered pleasurable is referred to as anhedonia.