Sometimes I read a sentence like the following one:

Objective-C does not provide a standard library, per se, but in most places..

I wonder how to interpret "per se." I'm non-native English speaker and in Swedish we have the expression "per se," but I don't understand it and maybe you can say that it means something like "in itself" (the strange Swedish expression is i och för sig) like Latin for de se as distinct from latin de facto, de re, de dicto, de jure, etc.

Do these expressions have a connection: "per se" and de se? Is it Latin and therefore I have difficulty to understand?

What is the difference between these sentences?

  • Breaking a traffic rule does not, per se, make you a burglar.
  • Breaking a traffic rule does not, per definition, make you a burglar.
  • Breaking a traffic rule does not, in itself, make you a burglar.

closed as general reference by F'x, Thursagen, simchona, Matt E. Эллен, kiamlaluno Aug 31 '11 at 11:59

This question is too basic; it can be definitively and permanently answered by a single link to a standard internet reference source designed specifically to find that type of information. If this question can be reworded to fit the rules in the help center, please edit the question.


It's supposed to show that the preceding part should be considered on its own merits without anything external, but it's often used to just emphasise that the preceding part is (not) really enough to explain the proceeding part or, as in your example, used as a high brow version of not really.

In your example, 1 and 3 are interchangeable. by definition is used in the opposite scenario.

per se is usually used in a negative construction, whereas by definition is usually used in positive constructions.

  • Thank you for the prompt good response. I think I understand and I can understand if there's a difference between "per se" and "in this case" like "A Volkswagen is not, per se, faster than a Ferrari" and it's like a non-implicative negation since a Volkswagen can be faster than a Ferrari and we don't know about the actual case, just what the rule doesn't imply. – Niklas Rosencrantz Aug 31 '11 at 6:32
  • per se is not /in this case/. It's /in and of itself/. – Lambie Mar 27 '17 at 13:45

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