Spreeuw
One condom isn't enough
Of course, that deontololgy and utlitarianism feed one off the other was central to my point that the OP would benefit from an introduction to ethics. Ethical questions are philosophical in nature and have no clear-cut answers, hence the fact that we still debate them.
Well, philosophically there are very different thoughts. My opening post was not about utilitarianism vs. Deontology.
Rational choice is not concerned about the most happiness of the most people, it's concerned with actor A getting most of what it wants, on the cost of other people if it's necessary.
Justice has more conceptions then one, util. deon. and teleo. schools of thought all have to do with ethics in the whole sense, but justice is only a little part of ethics (Who get's what, when, how, where?).
That being said, the different ethical schools definitely don't "feed off" the other. They are not arguing about what constitutes a certain action (intent, action itself or consequences) they are arguing what is most important for judging it's morality.
Ofcourse in everyday life everyone uses all three of them simultaniously, but you can't compare Machiavelli (pure (and thus immoral (not amoral)) consequentialist) with Kant (Pure deontologist).