I recently watched Interstellar and it was quite an amazing movie. There is something that has been bothering me. At the end, when Cooper is stuck in the time-space shelf created by the other beings (themselves/humans), he communicates with himself and Murph and he himself is the one to call himself in the space and save the earth by communicating the code back to his daughter.

My question is: If the future humans knew about the solution to the problem, why did they or Cooper chose himself to go through all the trouble to go through the space and then communicate with his daughter. Why couldn't they have done it themselves and sent the solution back to Murph themselves from the future.

Let me put it this way: "When Cooper saw himself from the shelf, why did he send himself the co-ordinates again. Why not just give Murph the solution only" Instead of sending himself the co-ordinates, couldn't he just have given Murph the solution. If the people of the future knew the solution (that they knew because that is how they survived) couldn't Cooper have just sent it to Murph from the future instead of going through the loop in space again?

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    This is kind of lame so I'll post it as a comment and not an answer, but it appeared to me as if the whole movie was some ever-continuing loop. It was always Future Cooper who communicated with Past Cooper. Commented Feb 4, 2015 at 15:13
  • Also, the first part was "officially" answered here: movies.stackexchange.com/questions/27112/… Commented Feb 4, 2015 at 15:14
  • @NapoleonWilson changed the question and removed the first one. Commented Feb 4, 2015 at 15:42
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    I guess answering with "That wasn't the point of the movie's story, it was about reuniting with his daughter" would be cheating? ;-)
    – Napoleon Wilson
    Commented Feb 4, 2015 at 15:44
  • That is what I'm saying; why leave her the first time to re-unite with her later when she is old. Why not just send her the solution from the future. Commented Feb 4, 2015 at 15:45

4 Answers 4


This is an interesting question because Cooper brings it up himself while he is in the tesseract, the bookshelf without time. He thinks that "they" choose him because of his love for Murph, and her's for him. IIRC, he says something like "Love is measurable" and that Brand was right in this regard. He suggests that "they" have chosen this specific pair of people because only Murph would believe in the "ghost" and its message and only Cooper could have transmitted it in this way. Even Cooper wouldn't have listened to future Cooper (his past self ignores the "STAY").

There is no definitive explanation in the movie. It only hints at this answer through Cooper's guess, the same way it only hints at who put him in the tesseract and created the anomalies.

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    Great point, in fact it goes even further, Cooper says that "they" have access to infinite time and infinite space, but no way to locate a specific event. Their omnipotence makes them basically insubstantial and they need him as a messenger to transmit anything.
    – Napoleon Wilson
    Commented Feb 4, 2015 at 16:17
  • I'd add that to these future versions of themselves, a person travelling into the heart of an enormous black hole might be a disturbance large or unique enough to latch on to... to have worked out everything else from that event in the past. There probably aren't all that many people who have done this.
    – Bon Gart
    Commented Mar 24, 2015 at 12:25

"They" don't understand human thinking. Modern "Cooper" Human thinking anyway. They have moved beyond us biologically and exist in 5 physical dimensions instead of 3. They don't know who or when really. They have a vague notion but nothing specific. That's where Cooper comes in. They built the means, but they can no longer figure out how to use it. Cooper and Murphy can.

Specifically, Cooper explains in the Tesseract, a fourth (fifth including time) dimensional representation of Murphys room folded in within itself. "They don't know when". If 3 dimensional space is huge, time makes it exponential.

Additionally they don't have the info Cooper has. Cooper knows, first hand, that Murphy and Brand senior are working on the gravity issue. He knows that Brand solved it except for time i.e. quantum mechanics meets special relativity. He knows the only way to get that variable is through observing the inside of a black hole. They don't know what the solution is, just the results of its use.

For comparison, I know how planes work, but I don't know the math behind it, or how to explain it to someone in the past. Nor do I know to whom I would give that to if I did. Or how to speak their language. If I traveled back in time far enough, me and Plato would have nothing in common and the info I have would be useless to him if I can't even explain it in his terms. Much less Grr the Homo Erectus or ooh aha the prehumanoid ape.

As for your last question, why they or coop didn't avoid the time loop, well, let's assume time in the movie falls into the immutable theory of time. You can't change it. It's a stable time loop. As TARS the lovable bastard states They didn't bring us here to change the PAST. Everything that happens has to happen in order to happen.


The fact that the coordinates were for the NASA base location was enough to make Cooper believe, and only he could make that happen when he was given the opportunity to communicate. He chose binary because the robot was limited to Boolean language..

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    Your statement about the robots being limited to Boolean language is completely wrong. CASE and TARS communicated in English with the human crew members throughout the ENTIRE movie. He used binary and Morse to communicate because the only way he could affect the past was by using gravity.
    – Doresoom
    Commented Jun 15, 2015 at 18:48

//"If the people of the future knew the solution (that they knew because that is how they survived)"//

I disagree that the 5th dimensional future humans are descendants of the survivors of Plan A or B. From their perspective, when they created the wormhole they were altering the past... so there must be some original timeline where there was no wormhole, there was no plan A or B but a few remaining humans still managed to escape the planet and colonize space... but they had to leave billions of people behind to die. It is these survivors, from this prime timeline, who created the wormhole... a life-raft for the billions they abandoned. Whether or not the paradox would erase them from existence, in the process, is another question. Maybe they couldn't live with the guilt.

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