The definition of "principle" is so generic that most principles are not worth squat. It is my opinion that a principle is simply anything which can be explained and understood. A principle does not need to be true, or even logical, as long as it can be explained and understood. A principle only becomes noteworthy as it implacts upon things that we are interested in.
In other words, we should not get excited about the word "principle".
What do you think?