(noun) A fundamental assumption or guiding belief. Example: "We need some sort of principles to reason from."
"Those are my principles, and if you don't like them, well I have others."
"A small knowledge of human nature will convince us, that, with far the greatest part of mankind, interest is the governing principle; and that almost every man is more or less, under its influence."
"Reason and experience both forbid us to expect that national morality can prevail in exclusion of religious principles."