ことができる versus V~える form?

Question

Way back in the day when I was first learning Japanese, I learned that you could add `ことができる` to a verb to indicate potential. Like so: > 食{た}べることができる > > *(I) can eat (something)* It became my habitual way of expressing possibilities. Then later, I learned that you could just modify the verb and get the same thing: > 食{た}べられる > > *(I) can eat (something)* I know that this is also the passive voice, but, unless I'm mistaken, it can be used strictly as a way of expressing potential. I still tend to habitually say `ことができる`, though. It tends to jump out of my mouth before I realize that I could have probably modified the verb. I think because my brain thinks they are the same thing, so I just go with the usual. So... are they different?

Answer 1

Largely, there is no difference.

~KOTO GA DEKIRU is used for the possibility of an outcome, while the potential (~RARERU, xERU) is used for the ability of an individual. The former also tends to be more formal/academic and less colloquial than the shorter ~RARERU/xERU forms.