Different ways of saying "impossible" - -得ない vs. -eない


What's the difference between ～得ない【えない】, as in, say, 届き【とどき】得ない【えない】, and
～eない, as in 届けない【とどけない】? As far as I can tell they both mean "it can't be
done," "it's impossible", but is there a difference in connotation or a subtle
difference?




届けない doesn't mean "something can't reach" but "to not deliver something" as
chocolate says.

Since 届くis an intransitive verb that doesn't stand for one's volitional
action, 届く doesn't have the potential form.

As for difference between ～得ない and potential forms, the former stands for
possibility under a certain condition while the latter does one's ability or
capability. So you can't use potential forms when the subject of a sentence is
linguistically inanimate like plants or something that doesn't move by itself,
in other words, you can say この木は大きくなり得ない or …大きくならない for "this tree can grow
big" but not この木は大きくなれない (in average people's sense).




届けない doesn't mean "something can't reach" but "to not deliver something" as
chocolate says.

Since 届くis an intransitive verb that doesn't stand for one's volitional
action, 届く doesn't have the potential form.

As for difference between ～得ない and potential forms, the former stands for
possibility under a certain condition while the latter does one's ability or
capability. So you can't use potential forms when the subject of a sentence is
linguistically inanimate like plants or something that doesn't move by itself,
in other words, you can say この木は大きくなり得ない or …大きくならない for "this tree can grow
big" but not この木は大きくなれない (in average people's sense).

