Moral philosophy takes two basic forms (there are also others, less common, like virtue ethics). One is morality that judges actions based on what consequences they have. This is known as teleology or consequentialism, and the most common form of consequentialism is utilitarianism or ethical hedonism: the belief in the greater good and that the best course of action is that that makes the most number of people well off and happy, or egoism, which sees actions that benefit the self as the most righteous.
The other basic form is morality that judges actions based on the principles behind the actions. This is known as Deontology. Examples of deontologist ethics include the principles that one should not lie, steal or kill because it is inherently immoral to do so, which counters consequentialist morality that in basis holds that it is okay and not immoral if there is a greater benefit to be had.
As a trope, ethical hedonism is For Happiness. When difficult decisions have to be made, it is The Needs of the Many. If utilitarianism is taken farther, it is expressed by tropes such as Totalitarian Utilitarian and Utopia Justifies the Means. Deontology as a trope is expressed through For Great Justice, and some light forms of deontology are related to The Golden Rule (do/don't do unto others what you would/wouldn't like others to do unto you). Darker and more extreme forms of deontology are expressed by tropes such as Principles Zealot. Characters that adhere to or pursues either moral principle to the extreme can be The Unfettered, Knight Templar, or a Well-Intentioned Extremist.
One could say that ethical hedonism tends more toward Chaotic Good while deontology tends more toward Lawful Good, although those are generalizations and in specific cases the opposite can be true (e.g. a deontologist might believe in a Chaotic Good duty to oppose an unjust law, or a utilitarian may hold a Lawful Good belief that a good government should be supported because it keeps everyone happy). Deontology stresses principles and duty to oneself and others, while consequentialism such as utilitarianism stresses keeping people, both oneself and others, as well off as possible. Epicureanism is one philosophy advocating ethical hedonism which started in ancient Greece.
Maximize happiness, minimize sufferingEthical hedonism's goal to make everyone as happy as possible, but achieving total happiness or happiness in every single person is unrealistic. Instead, it strives to create as much happiness as possible for as many as possible. This may include sacrifices such as making "the few" unhappy or creating destructive suffering as a necessary evil for the greater good, however it doesn't have to lead all the way down to Utopia Justifies the Means; it can stop at some much earlier point along the Sliding Scale of Unavoidable vs. Unforgivable between "wouldn't hurt a fly" and Totalitarian Utilitarian.
No matter how evil or destructive a person is, an ethical hedonist believes that it is a bad thing if that person is unhappy or hurt, as his happiness is just as important as anyone else's, and his suffering just as undesirable as anyone else's. An ethical hedonist would decide to harm a person only if it results in a greater amount of good or happiness for more people. An ethical hedonist would harm a Nice Guy for the same reason, though nice people are much less likely to be a subject of harm because they by nature do not intend to hurt people.
Abuse, violence and other violations or harmful crimes are immoral in ethical hedonism not because they are bad in principle as in deontological ethics, but because they result in suffering and sadness. Firstly, the acts usually generate more suffering and deprivation of happiness (for the victim) than it creates happiness (for the abuser or offender). Second, if abuse was accepted, then people would be more afraid and thus less happy. To prevent, stop or deter these action an ethical hedonist may find it justified to harm or otherwise deprive of happiness the person responsible, but not because the culprit is guilty or deserving of it, and the ethical hedonist would rather find a solution that does not hurt or make unhappy either party.
An ethical hedonist generally has no problem with lies and deceit as long as it's done in manner that does not cause harm or distress. She would rather let her fallen comrades die happy than letting her honesty go too far. Of course, in most situations ethical hedonism consider lies and deceit to be a bad thing, but not because it's bad in principle but rather because it has a tendency to have unforeseen bad consequences. When it seems clear that a lie will have no such bad consequences, an ethical hedonist may even see telling the truth as the evil action in that situation. This applies to many of the cases people view as "white lies".
Trying one's best for happiness is a required trait of any character who is an ethical hedonist without being hypocritical or a Hollywood Atheist. However, a character doesn't have to be philosophically inclined to be for happiness. The desire to make the world a better place through spreading or enabling happiness can come from anything from simple empathy to the religious worship of a deity that fits the concept.
The dark sideAn ethical hedonist character that strives for happiness generally doesn't try to force people to be "happy", remove free will altogether or otherwise commit gross violations for the greater good. Extending ethical hedonism that far pushes it into the realm of the Totalitarian Utilitarian and makes the character a Well-Intentioned Extremist.
However, given enough Insane Troll Logic, or simply a disconnect from empathy, human dignity and the spirit behind the principle, ANY principle can be twisted into something vile without violating it. Ethical hedonism is not immune from this trend, and it can be perverted either by interpreting "happiness" in a way that the person receiving the "happiness" wouldn't agree with, or taking the principle way beyond common sense to some narrow-minded extreme. There are three main such examples when ethical hedonism is philosophically taken to the Logical Extreme:
- We should maximize the average happiness, which can be done by killing off everyone who's unhappy. (This is like killing off short people to increase the average height of a population, or killing the poor to increase average wealth)
- We should maximize the total happiness, and since even starving people are capable of happiness, we should reproduce as much as possible. Even if these people are now living miserably because the social systems cannot support them, even if they carry only an ounce of happiness that is an additional ounce of happiness that the world gains.
- Negative utilitarianism: Instead of maximizing happiness, we should only focus on minimizing suffering. However, all living things suffer to some extent, so we should just put them out of their misery. (This assumes that death is not bad at all, and doesn't count as suffering.)