〜ていない vs 〜ないでいる


I read many times [this
question](https://japanese.stackexchange.com/questions/13635/%E3%80%9C%E3%81%AA%E3%81%84%E3%81%A7%E3%81%84%E3%82%8B-verb-
ending) but I'm still confused about the differences between these two
grammars. The first answer says that `〜ていない` has a possible third meaning not
used, " _I eat my meal and I am here (/I exist)_ " that is " _a terrible way
to read it_ ", and when it goes to explain `〜ないでいる`, it means " _I am here (/I
exist) without eating my meal._ " which seems very similar to the terrible way
of reading it.

Also, wouldn't `ていない` mean **"... and I'm not here"?** I appreciate the
efforts of the person who answered, but I really didn't understand it,
especially what **"instrumental adjunct"** is.

I'm not sure, but the difference between them seems to be how long the state
remains.

In `食べていない` I don't eat something since a long time ago, it remains until now
and it will remain in the future, `食べないでいる` on the other hand, would mean that
I'm in the state of not eating now, but that won't last too long.

The sentence that made me search about this grammar is: `僕が…書けないでいるから？` It's
an answer from person A to person B when asked why the person A is in the same
place as B.

Could someone explain the differences between these two grammars and when
should I use it?




Without complete predicate, it is hard to generalize the difference between
〜ないでいる and 〜ていない. So, I'd like to use `食べていない` and `食べないでいる` from your
example.

And, I have not understood what "instrumental adjunct" states clearly,but I'd
like to answer.

The author in the link might be explaining the sentence : `食事を食べないでいる` implies
"I want to be in the state of not eating ( in order to lose the weight, etc.
)" by stating _"I am here (/I exist) by not eating my meal." (instrumental
adjunct)_

I mean _"I am here by not eating my meal"_ implies to complete some purposes
of its action. So, `食事を食べないでいる` implicitly modifies some purpose such as
losing the weight, etc.

Consider the sentence `膝{ひざ}を怪我{けが}しているので、走{はし}らないでいる。` " _Due to the knee
injury, I try not to run ( the purpose : in order to get recovery in the knee,
etc. )._ "

So, your sentence : `僕が…書けないでいるから？` is possibly saying "I am here probably
because I could not write ( Due to the slump, person A does not have an idea
how to finish writing. )".

`食べていない` implies basically "not eating at this moment". It might imply
habitual action, progressive action, experiences, etc. such as " _I do not eat
X recently_ ", " _I am not touching the food to start eating_ ", " _I have not
eaten since this morning._ ", etc.

So, `膝{ひざ}を怪我{けが}しているので、走{はし}っていない。` could imply _"I do not run regularly due
to the knee injury"_.




Without complete predicate, it is hard to generalize the difference between
〜ないでいる and 〜ていない. So, I'd like to use `食べていない` and `食べないでいる` from your
example.

And, I have not understood what "instrumental adjunct" states clearly,but I'd
like to answer.

The author in the link might be explaining the sentence : `食事を食べないでいる` implies
"I want to be in the state of not eating ( in order to lose the weight, etc.
)" by stating _"I am here (/I exist) by not eating my meal." (instrumental
adjunct)_

I mean _"I am here by not eating my meal"_ implies to complete some purposes
of its action. So, `食事を食べないでいる` implicitly modifies some purpose such as
losing the weight, etc.

Consider the sentence `膝{ひざ}を怪我{けが}しているので、走{はし}らないでいる。` " _Due to the knee
injury, I try not to run ( the purpose : in order to get recovery in the knee,
etc. )._ "

So, your sentence : `僕が…書けないでいるから？` is possibly saying "I am here probably
because I could not write ( Due to the slump, person A does not have an idea
how to finish writing. )".

`食べていない` implies basically "not eating at this moment". It might imply
habitual action, progressive action, experiences, etc. such as " _I do not eat
X recently_ ", " _I am not touching the food to start eating_ ", " _I have not
eaten since this morning._ ", etc.

So, `膝{ひざ}を怪我{けが}しているので、走{はし}っていない。` could imply _"I do not run regularly due
to the knee injury"_.

