aru vs iru : Why is aru in "Watakushi-wa untenshu-ga aru" (私は運転手がある) unacceptable?

Question

There is a generally expressed rule in Japanese that, when declaring existence, いる is used for animate subjects, and ある is used for inanimate subjects. There are some interesting variations in what is considered to be animate, but there's one very well known exception to these rules.

私は子どもがXある - I have X children/As for me, there are X children.

いる is preferred in this sentence, but ある is permissible. I have heard the acceptability of ある in the above explained in two ways.

1. Children are "de-personified" in this structure, either because of linguistic humility or some other reason. In this case, intransitive ある maintains the usual distinction of working only with inanimate/non-moving subjects.
2. This is actually a different ある verb from the existence variant. In this case, ある is a transitive possessive verb meaning "to have, to own".

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Either of these explanations will work, but moving outside of this specific sentence presents me with a problem.

I have recently read that

×私は運転手がある

is not acceptable, even if 運転手 refers to a permanent servant working for the 私 in the above sentence. Why is this?

I would think it would be at least as acceptable to de-personify one's own servants as one's children. Rather obviously explanation 2 (possession) should allow this construction as well. What distinguishes these two uses of aru?

Answer 1

As noted in the comments, we all agree that 私は子供がいる is the usual way of saying you have children. The question is why is 私は子供がある permissible, but 私は運転手がある is not?

The verb ある can be written as 有る or 在る. The first is the one used in the rule "use 有る for inanimate objects and 居る for animate beings" and means "being (t)here". The verb 在る, like its 漢語 incarnation 存在, means existence and has a more essential flavour to it than a just being there. With more 漢字, the first sentence should thus be written 私は子供が在る.

This existence is closely tied to the person in question (私) in a way that the driver (運転手) is not. Thus one can say

彼は[田舎]{いなか}に[親戚]{しんせき}が在る。

but not 私は運転手がある, because the existence of your driver is not tied to you in such an inextricable way. You can change your driver, or fire him, in a way you cannot change (or fire) your children. (Well, you can fire them legally, by giving them free for adoption, but you cannot fire them biologically.)

Thus, it is just about possible to say

ブルース・ウェイン(ウェイン家)はアルフレッドと言う[忠実]{ちゅうじつ}なバトラーが在る。

because the butler's existence is tied to the Wayne family much like a family member.

Side note: (Judge for yourself, whether this is at all related to the question or to the answer.) Looking at the negation of ある, ない, we also have different 漢字, i.e. 無くなる and 亡くなる. As a negative analogue of the ある/いる rule above, we have the rule "use 無くなる for inanimate objects and 居なくなる for animate beings". The expression 亡くなる, however, is used for the verb "to die", but can also mean "to perish" or "to cease from existence" and is thus the perfect candidate for the negative of 在る, when used in the phrase 親戚が在る; you have (在る) relatives, until you don't have (亡い) relatives, because they die (亡くなる). If your relatives moved into town, you have to say that

[親戚]{しんせき}は[田舎]{いなか}から居なくなった。今[都会]{とかい}に[住]{す}んでいる。