As far as Jedi vs Sith goes, the important thing to realize is that they are all of them uniquely in a position of power, and their philosophies are fundamentally about what you have to do in that position.

The Jedi believe that you should not be, and cannot be selfish with that power, that using it for its own sake is bad, that restraint is the order of the day, because without it, you WILL eventually lose control and make bad things happen. They believe in personal responsibility and, by extension, have a lot of reasons to not do something.

Whereas the Sith are all about seizing power, using it for its own sake, indulging yourself, collecting more power, and generally not letting anything get in your way. The ends justify the means, and the end is personal empowerment at any cost. Calling it a philosophy is something of a misnomer even because all it really is, is an excuse to justify... anything. Everything. They think that if they can't be stopped, they shouldn't be stopped.