"Plurality should not be posited without necessity." Such is what is commonly referred to as Occam's razor, which, I have to say, is a great little piece of philosophy. It turns out to be a central element of the thesis in a paper I'm in the middle of writing for my Justice class. My thesis is essentially that John Stuart Mill adds no necessity and a bunch of plurality to Jeremy Bentham's utilitarianism and that Mill's revision should be discarded.
Occam's razor is really great for arguing things like this because it's so well known and not too many people will directly argue against it. People are more likely to argue against your application of the razor instead of the razor itself.
Oh man, I love writing philosophy papers.