What's the difference between 〜以上は and 〜からには?

Question

The textbook I'm currently using defines both of these grammar points as: 〜のだから、絶対にする／しないのが当然だ What is the difference between the two grammar points, can they be used interchangeably like the following: 自分でやると言ったからには、最後まで責任を持ってやってください。 vs 自分でやると言った以上は、最後まで責任を持ってやってください。 If they can be used interchangeably, is there any nuance I should be aware of?

Answer 1

Those two grammar points/phrases actually are different.

. ～以上は as suggested by the meaning of its characters means "more than", where the subject is before the phrase. For example, １０ドル以上は使いたくありません。translates to "I don't want to use [more than] 10 dollars. If you insert "more than" into the example phrase you gave, you will find it doesn't make sense.

On the other hand, ～からには has a nuanced meaning that emphasizes a condition/commitment. This phrase is a lot more similar to and sometimes interchangeable with ～のだから。In your example sentence, both ～からには and ～のだから work to express that the subject has said they would do something, thus referencing a commitment, and should therefore assume responsibility to follow through with it. "should therefore" is a way to translate this phrase with nuance, although it may differ contextually.

Hope this helps