(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."
"Reason and experience both forbid us to expect that national morality can prevail in exclusion of religious principles."
"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."