How does だからって usually work?

Question

馬鹿だからって知らないわけじゃない

I translated this sentence as "It's not like I don't know that I'm stupid," while my friend who wrote it translated it as "I'm stupid, but I know that." So I feel I understand the meaning adequately, but on closer inspection, I am confused by だからって. Is it two words, だから and って, or one word, or a set phrase?

WJD provides this definition: だからって (exp) even so; all the same; nevertheless; yes, but ...

So I suppose a better translation would be, "I'm stupid, but it's not like I don't know it," where だからって is equivalent to "but." However, does it mean more than "but" here? Is it also acting as a copula? What is the etymology of this expression and, if it is made up of two words, how do they act upon each other?

Answer 1

The って in からって is the quotative って, and there is a longer version which makes this clearer, から と 言って. These are interchangeable in all cases that I can think of. For some reason って is used in the short version, and と is common in the long version.

The below sentence might make it clearer how to understand/parse the phrase:

「馬鹿だから 知らないだろう」って 言っても、 知らないわけじゃない You might say that I won't know because I'm stupid, but it's not the case (that I don't know).

Note the the object of knowing could be any fact, not necessarily the fact that "I'm stupid"

The phrase means something like "It might be the case that ... , but ... ".

Some other usages:

暑{あつ}いからと言って[裸]{はだか}になるな It might be hot, but don't get naked.

お客{きゃく}だからって態度{たいど}が悪{わる}すぎる He might be a guest, but his attitude is still too shitty.

Answer 2

Indeed だ is the copula. And から means 'from'. In many languages, the word that corresponds to 'from' is often used as 'because'. って is contraction of といって, which originally meant 'saying', but has lost that meaning.

馬鹿だからって知らないわけじゃない
'It is not the case that I don't know it because (they say) I am stupid.'

And in this construction, P から 'because P' introduces a presupposition that P is true. That is why you can also translated it as:

'I know it even though (they say) I am stupid.'

Both you and your friend's translations are not correct. If you want to say something along the translation you give, then it has to be like:

馬鹿だということを{知らない/分かっていない}わけじゃない
'It is not the case that I do not know that I am stupid.'

Answer 3

The most idiomatic way to say it in English while avoiding the troublesome "but" would be

Just because I'm stupid that doesn't mean I don't know.

In fact I think the whole expression should be taken as だからって…ない with the negation being crucial (though sometimes implied*), and corresponds exactly to the English expression "Just because … doesn't mean … ". It expresses that "Your assertion that A is a sufficient reason for B is not valid".

If you look at だからって as だから (because) と (so) いって (saying), you can understand it as "saying it is so because". The ない then negates that assertion of causality: "Your saying that B is so because of A is not valid.", or "Just because of A (which is what you say) is not a valid reason for B.", which is equivalent to the English expression.

As sawa writes above, even in Japanese the meaning of って as "you say" is somewhat extraneous. I think it more easily becomes extraneous when expressed in English.

So your original sentence says that your being stupid is not a sufficient reason for (one's assumption of) your not knowing [some fact].

A asserts: You are stupid, therefore you don't know that fact.
B: That's not so. While I am indeed stupid, I do know that fact. 
   Therefore my being stupid does not imply that I do not know the fact. 

or

Just because I am stupid does not mean I do not know the fact.

• In dainichi's example お客だからって態度が悪すぎる I find the negative in the すぎる where "excessive" implies "not appropriate"; "his attitude is too shitty" is the same as "his attitude should not be so shitty". Though I may be reaching here.