Bentham advocated a quantity-centric version of utilitarianism. Moral actions are those that produce the greatest quantities of pleasure, or happiness, and the least amount of pain. All action, therefore, should be aimed at producing pleasure. Bentham articulates his view that pleasures and pains, which occur only in the individual, can be quantified.
Epicurus argued that a pleasant life is one free from distress, both mental and physical. Contrary to some common misunderstandings of epicureanism or hedonism, pleasure is not achieved by satisfying every urge. That is because not all desires lead to long-term pleasure, which is the goal. In addition, the worst sort of pain is psychological. Most physical pains are temporary, whereas psychological distress is often relentless.
According to Kant, reason generates a priori (independent of/prior to experience) the supreme principle of morality. That principle is commonly understood in terms of duty, that absolute obligation to do or refrain from doing something, out of respect for oneself as a rational being. For Kant, there is nothing of the empirical in morality; rather, morality is determined solely through reason.