Definition: A self-evident and necessary truth, or a proposition whose
truth is so evident as first sight that no reasoning or demonstration
can make it plainer; a proposition which it is necessary to take for
granted; as, "The whole is greater than a part;" "A thing can not, at
the same time, be and not be."
Definition: An established principle in some art or science, which,
though not a necessary truth, is universally received; as, the axioms
of political economy.
