To (hopefully) remove the worst of the confusion:
A German sentence in the present tense can be understood as a statement about the future if there are other expressions or contexts that make it unambigously clear what's meant. The given sentence here is one of the most common occurances of this special case.
Imagine it is 11 AM and you have a phone call with your best friend who wants to visit you in the afternoon. He tells you he could be there at five o'clock and you tell him you are sorry but you won't be there at this time.
This conversation might be as follows:
A: "Kann ich später noch vorbeikommen? So gegen fünf kann ich bei dir sein."
B: "Nein, tut mir leid. Ich bin zu diesem Zeitpunkt nicht da. Ich bin doch donnerstags von vier bis um sechs immer bei XY."
Both conversation partners know that it is not 5 PM now and that they are talking about something which might or might not happen at that time in the future. "Five o'clock" is a very concrete time therefore B uses "dieser Zeitpunkt" to refer to it. B says further: "(ich bin)[...] nicht da." So the question is what does B mean by using "da" and how can you translate it. Normally "da" is a specific place which is not the place B is currently in. In the case of the given sentence the (given or not given) context gives no information what "da" is referring to. In my example it is at B's place and it's absolutely possible that B is at home at the moment. So why does he refer to his home as "da"? Well actually, I don't know. As a native I know that it is factually used this way, but I can only make half solid guesses why this applies.
I'd assume that it is something like a byproduct of using the present tense while talking about the future. The concept itself has to seem rather philosophical to you, so please don't be too surprised if I tell you that your home in the future will not be/is not the same as your home is now. It is only a projection of the current reality of your home, which is always based on the assumption that nothing will change in the meantime.
Ookay... I guess it's fine if you skip the last paragraph. Never mind and have a nice day!
Thank you for explaining the German! However, we also need to consider to the English, which is very specific about 'this' vs. 'that'.
To a native English speaker, "I'm not there at THIS time" can only refer to the true present moment in time, i.e. now.
"I'm not there at THAT time" could be a general statement about what's typically true; or it could refer to a specific point in the future (using the present-tense-for-future, just like in German).
One could of course also indicate a specific point in the future with "I won't be there at THAT time" (using the future tense).
I don't know how widespread or colloquial this principle is in English-speaking countries (especially in the USA, where Duo is based). If it is still not included in the 'officially recognized' grammar, Duolingo should not accept it in order to remain consistent in dealing with colloquial formulations. You are welcome to research to what extent and where it is used and post the results here. With the right justification, such suggestions will be accepted and incorporated into the system at the next opportunity.
Events in the near future, are often put into present in German. e.g.
- kommst du morgen?
- Nein, zu diesem Zeitpunkt bin ich nicht da.
If you mean now, it's
Ich bin jetzt nicht da, if it's some other time, it it is as before.
That sounds like something a flight attendant would say.
- I will not be there then.
is far better.
Ich (subject) bin (verb, present but used about the future) zu diesem Zeitpunkt (at "that" period of time) nicht da (There, and the "nicht" negating "bin").
- I well not be there then.
Once again DL's translation is too literal.
Sure, but the point is, no matter what place and what time you choose to utter the words "Ich bin zu diesem Zeitpunkt nicht da", you in fact ARE at THE place and at THE time of this utterance, as you, well, utter it. So you would describe the place as HERE, not as THERE, as well as you are describing the moment as THIS moment and not THAT moment.
And that might be an answer to my original question: that THIS moment does not have to mean NOW, but possibly a moment specified in the course of a previous conversation distinctly enough to vouchsafe for using THIS instead of THAT.
Suppose an event happens weekly at 3:00 and again at 4:00 on Friday. You go for the first three weeks at 3:00. If you're going to be absent the fourth week you might say, "I won't be there this time." On the other hand, if you will miss the 3:00 event but can make the 4:00 one, you might say, "I won't be there at this time."
Funny, innit, when you fly anywhere, the flight crew say stuff like at this time, stow you personal belongings... ", and such and they mean now*?
So doesn't this sentence mean I will not be here now ?
Because "there" in English implies distance from the speaker, whereas "this" implies proximity, you would have to add a distancing expression to make good sense in English: "I will not be there TOMORROW (etc.) at THIS time." Note how many of our discussants instinctively change THIS to THAT in their examples.
I assume you are talking about
"Ich bin zu diesem Zeitpunkt nicht da."
"Ich werde zu diesem Zeitpunkt nicht da sein."
both translating to "I will not be there at this time.".
In German, we often use the present tense to describe something that will actually happen in the future, if there is something else that clarifies what time is being spoken of. The first sentence "Ich bin zu diesem Zeitpunkt nicht da." literally means "I am not there at this time", which doesn't make so much sense in English because this understanding of time is not transferable. Not the same, but reasonably close is the absence of a German counterpart to the English concept of the present progressive. This is a concept of time that cannot be expressed grammatically, but only with additional words that mark the progressive element in German.
No, I don't think so. While "Zeitpunkt" usually refers to a clock time, so that such a time specification usually has a margin of at least 5 to 10 minutes, "Moment" and "Augenblick", if they do not refer to now, but are part of a story/planning, are only extremely short periods of time, which usually only extend over fractions of a second.
If you say "Ich bin im Moment/Augenblick nicht da." you are usually talking about now, while you are speaking.
Well, in German it can be written in "Futur I"(future tense) as well as in "Präsens"(present tense) to mean something in the future. Since this sentence would not make much sense with the present tense in English, it is highly advisable to use the future tense to translate it.
Our German grammar is a living example of the fact that one can (in one's imagination) completely move into the future and speak from this point of view. This is something which does not exist in this form in the English language, therefore it is reasonable that some translations of such sentences may be difficult for English speakers.