Use of は in indirect quotes

Question

This question had the following example:

人間に上下はないと考えるアメリカ人にとって、日本の目上と目下の関係は面倒だろう ?

and the OP was asking about the meaning of は. I'd like to expand on this.

Firstly, I'm assuming that 上下は is part of 人間に上下はないと考える rather than being the topic for the entire sentence. It would seem strange to start with 人間に if the latter were the case.

That being so, my main question is, is it generally allowed to use は within an indirect quote? It feels weird to me. Probably because I know that (with exceptions) it isn't allowed in a relative clause. So, in the example sentence is the は allowed only because of the usual rule that ない likes to take は or is it just perfectly natural to have は in indirect quotes irrespective?

Finally, and perhaps this should be a separate question, I know that は is allowed in relative clauses for the purpose of contrast. Is it also allowed when making a negation such as 上下はない? I guess that is a form of contrast, but it's not clear to me.

Answer 1

I'm not sure how to best answer your question, but here goes:

is it generally allowed to use は within an indirect quote?

Yes, you can use は in indirect quotes. Although, I might be misunderstanding what you mean by "indirect quote", because I don't think it's always possible to determine if a quote is direct/indirect.

My dad said smartphones are man's worst enemies. お父さんはスマホは人間の天敵だと言ってたよ。

は is used after スマホ because "smartphones" is the topic of the dad's statement. Changing it to が would change the meaning of the sentence (albeit, slightly, 'cause I couldn't think of a better example).

So, in the example sentence is the は allowed only because of the usual rule that ない likes to take は or is it just perfectly natural to have は in indirect quotes irrespective?

You phrased it as if it is either or, but they are both true. は can be used in indirect quotes, but the reason for using は in this particular case is because of ない. That does not make "人間には上下がないと考えるアメリカ人" or "人間に上も下もないと考えるアメリカ人" an absolute mistake, either.