とは限らない
Not limited to/Not Necessarily
Plain form verb/い adjective + とは限らない
Noun/な Adjective + だとは限らない
とは限らない means not limited to, not necessarily, or doesn’t necessarily mean. The formation of this is actually kind of hard,
and due to the lack of とは限る, I recommend you just learn it as a と phrase.
If you want to see my analysis of what is probably going on, see the bottom. Else ignore it.
とは限らない is frequently used with 必ずしも (Neccessarily/must)
Examples
- 彼がいい人だとは限らない – He is not necessarily a good person.
- 背が高い人はバスケットボール選手とは限らない – Just because someone is tall doesn’t mean they’re a basketball player.
- 鳥といっても、とべるとは限らない – Even though they are a bird, it doesn’t mean they can fly.
- 犯罪者は必ずしも悪い人とは限らない – Criminals aren’t necessarily bad people.
Formation/Analysis
This next section should be skipped. Let me know in the comments if you think I should delete it or move it elsewhere.
とは限る doesn’t exist, but と限る (sometimes) and に限る do.
For these reasons in part, we should just treat it as a phrase and move on.
But I tried to analyze it anyway.
My analysis of what is probably going on:
とは – Is probably quotation と + topic marker は. (appears to be the general consensus).
I considered とは (definitional), but it didn’t really make sense.
かぎる – an intransitive (usually) verb meaning “to be limited“. (NOT to limit).
限らない – to be not limited. (not unlimited).
I attached an “it is” to the sentences as I feel they are necessary to understand what is happening.
“It” here is “The truth”.
Sentence Analysis
と＋は:
彼がいい人だとは限らない → [彼がいい人だ」は限らない -> “He is a good person” is not limited (to) →
It is not limited to he is a good person.
とは:
彼がいい人だとは限らない -> 彼がいい人だ とは 限らない → (It is)”He is a good person” is “not limited to”
It is “he is a good person” is “not limited to”. (Just kind of wrong).
Annoyingly, とは (definitional) would have seemed to be the better choice because とは限らない is very similar to とは言えない. However, とは言えない uses a potential form verb, and uses 言う (Which gives us an implied subject) which is probably why that phrase is easier to interpret.