What is the purpose of 「で」 in the following sentence?


I came accross the following passage in my textbook:

> ゆとり教育で学校で教える内容が減らされたため、その教育を受けた子供達は常識的に誰でも知っているはずのこと **で** さえ知らないという現象も出てきた。

I can understand the meaning of the sentence, as "Due to the decrease of
contents taught at school as a result of ゆとり教育, the phenomenon of children who
underwent that education and don't know even things that anyone should
commonly know, also happens."

Since 誰でも知っているはずのこと is the object of 知らない I would rather say directly:

> 誰でも知っているはずのことさえ知らない

Without any "で". i.e., if we were to remove the "さえ", it would apply "を":

> 誰でも知っているはずのことを知らない

I don't understand what is the function of で here. What am I missing?

よろしくお願いします。




In short, でさえ is an alternate form of さえ and means the same thing (though not
interchangeable in all syntactic contexts). で here comes with さえ. **で does not
have its own function** (e.g. locational), it simply comes attached with さえ.

[Difference between
さえ、でさえ](https://japanese.stackexchange.com/questions/36397/difference-
between-%E3%81%95%E3%81%88-%E3%81%A7%E3%81%95%E3%81%88) explains it well
enough (check links and comments).

It's acceptable to say:

  * こと **さえ** 知らない
  * こと **でさえ** 知らない
  * こと **を** 知らない

However, it's much, much less common to say **をさえ** 知らない. The さえ usually
replaces the を. (This is similar to how one would say リンゴが好き。ドリアンも好き。 but you
wouldn't say ドリアン **がも** 好き.)

/// If you were to completely remove でさえ, you would get:

  * ...誰でも知っているはずのこと知らない...

Which is possible, [since dropping certain
particles](https://japanese.stackexchange.com/questions/80583/is-there-a-
particle-dropped-in-the-
sentence-%E3%81%8A%E5%B1%8A%E3%81%91%E7%89%A9%E3%81%84%E3%81%9F%E3%81%97%E3%81%BE%E3%81%99)
(を in this case) is possible and normal, especially in **informal** speech.

