心配する with implied object

Question

My apologies to @Chocolate for continuing to nag about this question (or if I've misunderstood your comments).

According to the link it is unnatural (ungrammatical?) to say:

1) 就職しないと心配する。 where と is used to mean 'if'
If I don't get a job I'll worry.

Instead, I should say:

2) 就職しないと、心配になる。

As I understand it, the reason that using 心配する is wrong is because there is no object.

However, this sentence is fine:

3) 早く帰らないと(if)、親が心配する。
If I don't hurry home my parents will worry.

This sentence is fine because there is an implied object: 親が私を心配する. My parents will worry about me.

But I'm struggling to see how sentence 1) and sentence 3) are fundamentally different. Why can't there be an implied object in 3) which might be 就職できないこと?

I'm happy with sentence 2) but is 1) completely wrong or just a bit awkward (ignoring, if possible, the fact that you normally might/will treat と as quotative)?

Answer 1

I think one way to see the problem here is to focus on the restrictions when using と to mean "if". In particular, the restriction that what comes after と should not be a volitional sentence.

In the words of 新完全マスター文法N3, on page 91:

「～たら…」の…はどんな文でもいいが、「～ば…・～と…」の…には話者の意向を表す文や働きかけの文は来ない

The … of ～たら… clauses can be any kind of statement, but the … in ～ば… or ～と… clauses cannot express the speaker's intentions or inducements of others.

In your first sentence, it seems like "心配する" reflects the speaker's intentions. In contrast, "心配になる" expresses an uncontrollable event rather than an intention, since it seems like the speaker will start worrying beyond their control. Therefore, "心配になる" fits better than "心配する".

In sentence 3, it is the parents who will worry, which is something that the speaker has no control over and thus does not express the speaker's intentions. Therefore, this does not go against the grammar rules for using と to mean "if".

Of course, it's also important to make sure that the necessary complementary information of the verb is present or possible to infer from context (who is worrying? what are they worrying about? etc). I think you've already explored this aspect of the problem... but the following reference on the formation of the verb might be useful: http://niwanoda.web.fc2.com/kanjou2.html#sinpai