1. Utilitarianism is a kind of consequentialism
Utilitarianism evaluate the morality of actions on basis of their probable outcomes or consequence

2. Four Theses of Utilitarianism
Consequentialism: The rightness of actions is determined solely by their consequences.
Hedonism: Utility is the degree to which an act produces pleasure. Hedonism is the thesis that pleasure or happiness is the good that we seek and that we should seek.
Maximalism: A right action produces the greatest good consequences and the least bad.
Universalism: The consequences to be considered are those of everyone affected, and everyone equally.

3. Two Formulations of Utilitarian Theory
- Principle of Utility: The best action is that which produces the greatest happiness and/or reduces pain.
- Greatest Happiness : We ought to do that which produces the greatest happiness and least pain for the greatest number of people.

4. Two Types of Utilitarianism
Rule: An action is right if and only if it conforms to a set of rules the general acceptance of which would produce the greatest balance of pleasure over pain for the greatest number (John Stuart Mill)
Act: An Action is right if and only if it produces the greatest balance of pleasure over pain for the greatest number. (Jeremy Bentham)

5. Application of Utilitarian Theory
If you can use eighty soldiers as a decoy in war, and thereby attack an enemy force and kill several hundred enemy soldiers, that is a morally good choice even though the eighty might be lost.
If lying or stealing will actually bring about more happiness and/or reduce pain, Act Utilitarianism says we should lie and steal in those cases.

6. Criticisms of Utilitarianism
If I am to bring the greatest happiness to the greatest number, not putting my own happiness above others, that may lead to a dilemma. I live in a neighborhood where 83% of my neighbors use drugs. I could make them most happy by helping supply them with cheap drugs, but I feel uncomfortable doing that. What should a utilitarian do?