What is the は doing in this sentence?


In this [question](https://japanese.stackexchange.com/questions/15467/this-
mother-doesnt-know-her-own-child/15468?noredirect=1#comment33694_15468), we
are presently trying to better understand the function of the は that happens
here:

> 当時{とうじ}母{はは}がどんな気持{きも}ちだったのか、子{こ}どもの私{わたし}には知{し}るべくもないことだった。

meaningwhise, we are all agreed that the sentence means:

> As a child I had no way of knowing how my mother felt at that time.

(I'm just going with ssb's translation).

My question here is: can the は after 子供の私に be removed or does that make the
sentence ungrammatical? / Is this は just a topic marker? a topic marker and a
contrastive marker? or something further?




Edit:

I just remembered that there is a には which can not be replaced by に or は. It's
similar to にとっては, which might fit better here. e.g.

[code]

    それは私にはどうでもいいことだ
    その頃の私には、夢にも思っていなかった事だ
    
[/code]

This kind of には is inherently contrastive so you always use は. (But にとって is
still contrastive without は, it's a litter hard to explain.)

Whether this には in included in the scope of the subordinate clause is a little
tricky. You can say something like:

[code]

    わたしには、それは、大切な宝物です。
    子供の私には、それは、知るべくもないことだった。
    
[/code]

But you can definitely use it in subordinate clauses without dropping the は.

I can't find much explanation in dictionaries. 大辞林 has only a single line for
it:

[code]

    「…にとっては」の意を表す。 「ぼく－，ぼくの考えがある」
    
[/code]

But it's not clear if this には is に + は, e.g. people say

[code]

    私にいい考えがある
    
[/code]

大辞泉 does not mention this usage.

The following is a part of the original answer.

* * *

I personally believe “topic は” cannot be solely semantically defined, because
I can't find reasonable criteria and even Japanese linguists seem to disagree
on the scope of “topic は”. e.g. some linguists consider “には” and “では” as
“contrastive は”, while some think they are “topic は”.

If we talk about the “topic は”, I think we usually means:

  1. It's often used in the main clause and can't be omitted

  2. It's often not used in subordinate clauses.

For other kinds of は, they may freely appear in relative clauses.

The structure of your sentence can be understood as follows

> [...]どんな[...]だったのか(、それ)は、子供の私には知るべくもないことだった。

In this sentence, the は appears in a subordinate clause, so it's not likely to
be a topic は.

I also think “contrastive は” is the origin of all other はs. Different はs may
functionally overlap so it's possible a single は has several functions or
several different は appears in the same sentence.

Arguably “topic は” is always contrastive, because everything is different.




Edit:

I just remembered that there is a には which can not be replaced by に or は. It's
similar to にとっては, which might fit better here. e.g.

[code]

    それは私にはどうでもいいことだ
    その頃の私には、夢にも思っていなかった事だ
    
[/code]

This kind of には is inherently contrastive so you always use は. (But にとって is
still contrastive without は, it's a litter hard to explain.)

Whether this には in included in the scope of the subordinate clause is a little
tricky. You can say something like:

[code]

    わたしには、それは、大切な宝物です。
    子供の私には、それは、知るべくもないことだった。
    
[/code]

But you can definitely use it in subordinate clauses without dropping the は.

I can't find much explanation in dictionaries. 大辞林 has only a single line for
it:

[code]

    「…にとっては」の意を表す。 「ぼく－，ぼくの考えがある」
    
[/code]

But it's not clear if this には is に + は, e.g. people say

[code]

    私にいい考えがある
    
[/code]

大辞泉 does not mention this usage.

The following is a part of the original answer.

* * *

I personally believe “topic は” cannot be solely semantically defined, because
I can't find reasonable criteria and even Japanese linguists seem to disagree
on the scope of “topic は”. e.g. some linguists consider “には” and “では” as
“contrastive は”, while some think they are “topic は”.

If we talk about the “topic は”, I think we usually means:

  1. It's often used in the main clause and can't be omitted

  2. It's often not used in subordinate clauses.

For other kinds of は, they may freely appear in relative clauses.

The structure of your sentence can be understood as follows

> [...]どんな[...]だったのか(、それ)は、子供の私には知るべくもないことだった。

In this sentence, the は appears in a subordinate clause, so it's not likely to
be a topic は.

I also think “contrastive は” is the origin of all other はs. Different はs may
functionally overlap so it's possible a single は has several functions or
several different は appears in the same sentence.

Arguably “topic は” is always contrastive, because everything is different.

