100330
I have recently learned that apparently [non-volitional verbs cannot have
potential forms](https://www.imabi.net/potential-i-potential-form).

> Non-volitional verbs cannot have potential forms. This includes verbs of
> natural phenomenon like 降る, 光る, 流れる, and 凍る, those concerning human emotion
> and physiology (痛む, 痺れる (to be paralyzed), 羨む (to be jealous), any verbs
> that end in ある (as they have no volition), and any pattern that has no
> control involved like phrases with つく and いく such as 想像がつく (one can imagine)
> and 納得がいく (to accept as valid).

So 光れる and 凍れる for example are not valid conjugations? Is this invalidity
strictly a structural limitation or is it semantic?

For example, I feel like "able to shine" or "able to be frozen" are reasonable
concepts with semantic meaning. What about rephrasing as 光ることができる or 凍ることができる?
Are these ungrammatical as well? If not, I don't see the problem with the
potential form.
CC BY-SA 4.0
2023-07-21T08:27:48.310
100328
2023-07-22T07:35:32.120
35041
question
grammar potential-form
Potential form of non-volitional verbs
> 光れる and 凍れる for example are not valid conjugations? Is this invalidity
> strictly a structural limitation or is it semantic?

I think it is more natural to say they are not idiomatic. Structurally, there
is nothing wrong with them. Everybody will conjugate 光れる as 光れない etc if forced
to.

> 光ることができる or 凍ることができる?

These are not idiomatic either. As you understand, the potential forms sound
like subjects do the shining or freezing at their will. In reality, there are
no such things (光れる does not apply to fireflies either). At the same time, it
is easy enough to imagine that there are anime or game characters that 光れる or
凍れる. (Note 凍れる is _able to freeze oneself_ rather than _able to be frozen._ )
Even if these do not sound too natural, they make sense in some contexts (I
guess 光を出せる or (自分を)凍らせられる may be used for such characters).

* * *

Cf.

  * 発光する can mean _to glow (in the dark)_.
  * 冷凍できる means _able to be frozen/freezable_ (for food).
CC BY-SA 4.0
2023-07-21T09:41:18.730
100329
2023-07-21T09:41:18.730
45489
100328
answer
凍れる is (almost always) invalid not because it's syntactically prohibited as a
rule but because it's (almost always) nonsense. The use of the れる form is
limited to one's ability, potential or right; you cannot use it to describe
the possibility of something happening.

  * Anything can happen.  
どんなことも起こりうる。  
(×どんなことも起これる。)

  * That can be true.  
本当かもしれない。/ それはありえる。  
(×本当であれる。)

  * This lake can freeze in winter.  
この湖は冬に凍ることがあります。  
(×この湖は冬に凍れます。)

できる is also for ability, so you cannot say この湖は冬に凍ることができます, either. As a rule
of thumb, whenever you want to translate "can", think if you can replace it
with "be able to" or "be allowed to". Since "This lake is able to freeze" is
strange, so is 凍れる.

However, you _can_ use 凍れる when you are actually talking about someone's
"ability to be frozen". For example, if a character like
[Iceman](https://www.marvel.com/characters/iceman) lost his ability to turn
into an ice form, he might say もう凍れないんだ or もう凍ることはできないんだ. The same is true
with 光れる. In [this song](https://j-lyric.net/artist/a043098/l024ce4.html),
there is a metaphorical phrase もう光れない ("We can't shine any longer") as if he
were a star in the sky.
CC BY-SA 4.0
2023-07-21T10:09:16.333
100330
2023-07-22T07:35:32.120
2023-07-22T07:35:32.120
5010
5010
100328
answer