In pursuit of sound principles

Add comment October 25th, 2008

A “principle” can be “the ultimate source, origin or cause of something,” “a natural or original tendency, faculty or endowment,” or, most commonly, “a rule of conduct” or “a fundamental truth, law, doctrine or motivating force.” It’s the correct word for the phrases “on principle” and “in principle,” the latter meaning “theoretically or in essence.”

It can only be a noun. The adjective in “principled.”

The homonym “principal” can be an adjective, meaning “first in rank, authority, importance, degree, etc.” This sense is conveyed as a noun for various major players, including the top administrator at a school, who has to deal with unprincipled students; the main members of a law firm; or the key actors in a play or business deal. It’s also the right “principal” for things financial — the amount of a loan or investment that isn’t interest, fees and other such things.

Both words come from the same Latin root that gives us “prince.” A principal might be a princely fellow, but Machiavelli’s “Prince” is a person of questionable principles.