Major William die in a combat versus aliens. Now he have the capacity to wake up on the same point of time every time he dies. (Movie: Edge of tomorrow)

He uses this power to win the war, but he has to memorize every single movement he do in order to save their soldiers and their own life.

Logic says he eventualy gonna do it, but repeating the day one million times It's like having lived more than two thousand years, probably losing their sanity.

My question is: It's our mind and memory precise and capable enough to repeat exactly the same actions and memorize it to make the day repeat in the same way as the previous one?

A little related to that other question: What is the limit of a human's memory if Immortal?

  • $\begingroup$ Well, I think it's worth wondering: in your scenario, can the subject develop muscle memory? Because that would affect the answer, given a HUGE amount of iterations (as in Groundhog day) $\endgroup$
    – xDaizu
    Aug 26, 2016 at 9:27
  • $\begingroup$ I'm not an expert about muscle memory, but I say yes. He can not change their body (like gaining strength), but can remember how to move. $\endgroup$
    – Malkev
    Aug 26, 2016 at 9:53
  • $\begingroup$ If at all, he is sending information back in time. And this information is stored on his brain. Yet, the way the brain stores such information is - at least in part - by the strength of its neural connections. So if he remembers, I would argue that he is changing his brain. $\endgroup$
    – Theraot
    Aug 26, 2016 at 9:56
  • $\begingroup$ He does not need perfect memory of everything to do, just where the danger will appear and the general strategy that is effective. He may remember something like "enemy will pop by that rock, I run for it a few seconds and then fire as it starts appearing" and leave the little details (where exactly did he step, if he aimed a little higher and lower) undecided. After all, if he misses he can just repeat it the next day, he does not need 100% perfection since dying is "free". $\endgroup$
    – SJuan76
    Aug 26, 2016 at 10:00

2 Answers 2


I side on Yes.

The argument for No, is on episodic memory which is not reliable. But I think this will eventually fall on procedural memory.

Now, it is known that the human brain - regardless of age - has some level of plasticity. That means that the human brain never loses his ability to acquire new skills, the human brain can always change the neural connections and create new habit.

So, I would argue that his multiple revivals would cause the structure of his brain to change, in a similar fashion in which the brain changes by prolonged practice in complex environments.

And since he is doing the same tasks over and over, the nature of this tasks would become mechanical*. And so, he will be able to learn them by practice, not dissimilar to learning to play a musical instrument or learning a particular choreography. There is no need for him to learn the whole thing at once, he may learn just the initial parts and master them, and then move to next situation, etc...

*: once he has decided what the correct course of action is and committed to it, and once he is past any gross factor.

Given that, I would expect that after enough iteration William will be doing the repeated actions out of habit, without putting much thought on the matter. In fact he will not only do them naturally, but also with better accuracy and even develop a sense for the timing needed to execute them.

My question is: It's our mind and memory precise and capable enough to repeat exactly the same actions and memorize it to make the day repeat in the same way as the previous one?

I say, yes.

Yet, as side effect he may require assistance to recover old skills. Take for example the case of learning to ride a backwards bike, after it is done, the person has a hard time driving a regular bike, but provided some practice, it is possible to acquire both skills.

Note: Some people say they forget a language when they learn another, but reality is that they only need a little practice to recover any lost vocabulary of their prior language - although this is anecdotal.

About his episodic memory of events prior to the point to which he goes back... he will not be able to recall. And his sanity... honestly, I don't know... but I can imagine him falling to doing some portions of his war routine without noticing, like a tick or a bad habit.

  • $\begingroup$ Surely his actions change slightly every day so he will remember something different each time and not build up this repeat memory. $\endgroup$ Aug 26, 2016 at 9:37
  • 1
    $\begingroup$ @Bellerophon Surely each time you try to play a melody in some instrument you execute it slightly different, that doesn't mean you cannot improve. $\endgroup$
    – Theraot
    Aug 26, 2016 at 9:39
  • $\begingroup$ Yes but messing up a note half way through the melody won't change the rest of the melody. Changing one part of a battle will Change all of the rest of the battle. $\endgroup$ Aug 26, 2016 at 9:41
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    $\begingroup$ @Bellerophon ok, I agree on that. So he will not be able to memorize what to do after the point on which he screwed up. Good, have him learn that next note - by whatever many iteration it takes - and them move to the next one. If there is no limit to the number of iteration, he will get there. $\endgroup$
    – Theraot
    Aug 26, 2016 at 9:46
  • $\begingroup$ Yeah, you might be right there. +1 $\endgroup$ Aug 26, 2016 at 9:47

Short answer: No

The human memory is amazing and very accurate but it does not have the scope to remember everything that happens in one day. Further to that, human perception is not 100% accurate. It works by guessing what the world will look like then comparing that guess with sensory input. This means things in the corner of the eye would not have enough sensory input to compare to the expected model so things that our protagonist is not concentrating on will appear in his memory as his minds best guess so even if he remembers everything it still won't be accurate enough for his purpose.

Furthermore, even if he does learn the day by repetition and muscle memory as soon as he makes a change his memories are invalid and he must learn this new future. He may also confuse the two futures leading to him making the wrong deductions. Obviously if he makes a second change he now has another future to learn and three futures to keep straight.

  • $\begingroup$ Of course, that's the point. He try to do all the same things to the moment when something goes wrong and then change it. This is something like try and error having to repeat all the day every single time. $\endgroup$
    – Malkev
    Aug 26, 2016 at 9:51
  • $\begingroup$ @Malkev My point is he won't be able to learn the new future and remember the steps leading up to it because he has to remember maybe 100s of different futures without getting them confused. $\endgroup$ Aug 26, 2016 at 9:59
  • $\begingroup$ He don't need to remember all, just the one he considered the better and follow it. Probably arriving sometimes to a dead end having to return to a previous point, but he don't need to memorize all the possibilities, just the part of the day he already considered optimal. $\endgroup$
    – Malkev
    Aug 26, 2016 at 10:04
  • $\begingroup$ @Malkev He will still be remembering the old methods though. I can still remember stuff that I no longer need/use. $\endgroup$ Aug 26, 2016 at 10:06

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