Utilitarianism

It is a teleological theory as each action or rule is judged on whether its end (tells) result maximises good. It is also consequentialist as the consequences of an action or rule determine whether it is right or wrong.
It is based on a posteriori knowledge - known by logical deductions made from observation and experience of the material world.
Utilitarians base goodness and righteousness on human experience. For them what is good is that which produces pleasure, happiness, contentment or welfare and what is right is that which maximises one or more of these things.
The method for maximising good is called the principle of utility.

There are three different strands of utilitarianism:
Act utilitarianism
Rule utilitarianism
Preference utilitarianism

Origins:
Jeremy Bentham and John Stuart Mill, the most important of the classical utilitarians, both agreed that:
In nature things and actions either cause pleasure or pain.
Pleasure is good and pain is bad.
The utility (meaning usefulness) of an action or thing is to be judged solely on whether it maximises pleasure.
An action should lead to the pleasure or happiness of the maximal number of people in society.
All human beings prefer pleasure to pain and this preference is built into nature's laws.

Jeremy Bentham developed an ethical…