The “se” in “per se” is a Latin 3rd-personal pronoun. This knowledge, combined with familiarity with the English use of “per,” yields the meaning, “in accordance with itself” or “in itself.” The term is defined in law as “intrinsically,” “inherently,” or “on its own merits.” For example, for a thing to be admirable per se, it must be universally admirable—admirable in a vacuum, without regard to law and culture. “Per se” describes the essence of what it is attached to; it’s a measure of whether a term describes a given situation on its most basic level.
While a collision at an intersection at which there was a yield sign indicates that someone failed to yield, such a collision does not constitute negligence per se. Thus, the actual definition of “negligence per se” is not left up to the discretion of a “reasonable person,” but specifically identified as “negligence due to the violation of a public duty under a law that defines the failure of care required to constitute negligence.”
We can tweak a scene from a popular film—Legally Blonde—to demonstrate the meaning of “per se” as it functions practically. During Elle’s criminal law course, she is asked whether she would prefer to defend a client who is guilty of a malum prohibitum or one who had committed a malum [per] se (actually “malum in se” in the film; but their translated meanings are virtually identical). Her classmate explains the meaning of both terms by answering that she would prefer to defend a malum prohibitum because “the client would’ve committed a regulatory infraction, as opposed to a dangerous crime.” The malum prohibitum (“restricted misdeed”) is simply a broken rule; whereas the malum [per] se (“crime in itself”) is inherently wrong or wicked.
Other Important Information
Negligence per se is supposedly negligence by any standard; but the standards of negligence are still laid out in the law to allow for human differences in judgment.