John Stuart Mill proposed a theory contrast to Kantianism. According to Mill, an action is good if it benefits someone; an action is bad if it harms someone. This ethical theory, is called utilitarianism, is based upon the Principle of Utility, also called the Greatest Happiness Principle.
Considering pleasure as a positive number and pain as a negative number a moral evaluation of an action is made by simply adding up, over all affected beings, the change in their happiness and if the sum is positive, the action is good. If the sum is negative, the action is bad. To measure them, he proposed seven attributes that can be used to increase or decrease the weight of a particular pleasure or pain:
- Intensity: Magnitude of the experience
- Duration: How long the experience lasts
- Certainty: Probability it will actually happen
- Propinquity: How close the experience is in space and time
- Fecundity: Its ability to produce more experiences of the same kind
- Purity: Extent to which pleasure is not diluted by pain, or vice versa
- Extent: Number of people affected.
Mill’s utilitarianism is simple and comprehensive to measure moral behaviour and a straightforward way to determine whether an action is good or bad.