Yet another question on 「は」 and 「が」


Below are two excerpts from the short novel
「[タクシーに乗った吸血鬼](http://www.nicovideo.jp/watch/sm17173268)」 by Murakami Haruki:

その一

> 「でもね、本当に吸血鬼がいたらどうします？」
>
> 「参っちゃうだろうね」
>
> 「それだけですか？」
>
> 「いけないかな？」
>
> 「いけないですよ。信念というのはもっと崇高なもんです。山 **が** あると思えば山 **が** ある、山 **が** ないと思えば山 **は**
> ない」

その二

> 「お客さん、信じてませんね？」
>
> 「ん？」
>
> 「私が吸血鬼だって……信じてないでしょう？」
>
> 「もちろん信じてるよ」とあわてて僕は言った。「山 **が** あると思えば、山 **は** ある」

The questions:

  1. I read [the post](https://japanese.stackexchange.com/questions/1077/why-is-the-topic-marker-often-used-in-negative-statements-%e3%81%a7%e3%81%af%e3%81%aa%e3%81%84-%ef%bd%9e%e3%81%a8%e3%81%af%e6%80%9d%e3%82%8f%e3%81%aa%e3%81%84) on the topic marker used in negative statements (as a contrast marker), but I can not see what the mountain in excerpt 1 is contrasted with. Is it contrasted with **the** mountain that turns into being when you believe there **is** a mountain? Or is it contrasted with **anything** else that does exist? Is it really contrasted with anything at all?
  2. I have no idea why 「は」, instead of 「が」, is used in the second occurence of 「山があると思えば山（ **は/が** ）ある」 in excerpt 2.




As for why it says 山はない in the first example

Since は is attached to 山, instead of 山がありは（しない）, it doesn't stand for contrast
between being and not being. In addition, the prior information is the same 山.
So, it's not really reasonable to think that it contrasts with something. In
this regard, you could explain that it sets a new secondary topic under the
primary 信念というもの. But it's more straightforward to say that it simply agrees
with the negative predicate. This is kind of a conventional usage and doesn't
have particular reasons. You could even say it's because it's familiar with
your mouth.

**Edit:** There's a room to interpret that the second 山 is recognized as an
old information that corresponds with the first 山, that is, "If you believe,
you get **a mountain**. If you don't, **the mountain** goes away".

As for why it says 山はある in the second example

As you say, 山がある would be just natural here because it's a consequence after
the conditional clause, which functions as a topic in a sentence. You don't
have to topicalize it. However, if you nevertheless do it, it conveys an
effect to make listeners wonder what will happen to 山 then when it's presented
as a new topic, and bring the consequence a bit delayed, which is so to speak
a nuance of "after all" or "indeed" as A.Ellett says.




I would say that in the first instance the ideas being contrasted are the
**effect** of belief: ie., _whether_ you think there's a mountain or not. So,
the idea expressed by 山はない is contrasting against idea in 山がある.

Normally what we think about things (like mountains or vampires) does not
effect whether or not there is indeed a mountain (or vampire). If I were to
try to capture this in English, I would write it something like,

> If you think there's a mountain, then there's a mountain. If you think there
> isn't a mountain, then there's _no_ mountain.

In the second instance, I would say this is an instance of _emphasizing_ the
mountain. It would be almost like saying,

> If you think there's a mountain, then **indeed** there's a mountain.

Granted, there's no word in the Japanese that corresponds to the word,
"indeed". But the feeling created by は here (particularly because it says
もちろん信じてるよ」と **あわてて** 僕は言った) is that of emphasizing the consequence of the
belief.

Since I haven't read the story, my guess about what's being said is that if
you believe there's a vampire there, well, in effect, there is (because you're
going to act accordingly). If you don't believe there's a vampire there, then
there isn't (again in terms of how you act).

