It seems that for a computerized simulation of what we call reality, there should be some moments where the simulation fails or is flawed in some way. In the movies, we are told that deja-vus are because a change is introduced in the matrix.

So why don't the machines simply rewind the simulation (a kind of time travel backward in time) until the illusion is maintained and erase the memory of any kind of perceived repetition? Is it because there is no real point in doing so since most humans won't think twice about it? Would it just be considered as what we call "paranormal" in our own "reality" and be debunked by mainstream science as "imaginary"? Or could it not lead to a mass awakening of people if left unchecked?

  • Why would the machine change the timeline of the entire Matrix coding just to eliminate so many trivial glitches?
    – Kinzle B
    Aug 4, 2017 at 23:11
  • Besides, I think most of glitches will go unnoticed and don't need the system to debug them.
    – Kinzle B
    Aug 4, 2017 at 23:19
  • That is one possibility. I guess it would depend on how many changes they make, but if humans start waking up fast without the bug they would definitely need to debug this as it would slow down the awakening and maintain the illusion longer.
    – Hermetix
    Aug 4, 2017 at 23:26
  • Rewinding the simulation doesn't sound straightforward to me. Are the machines even capable of erasing people's memories like that? Seems likely to cause far more trouble than it would solve. Keep in mind that the humans aren't themselves being simulated, they are just living in a simulated world. As for your other questions, I think there were several hints in the movie that paranormal phenomena (e.g., spoon bending) are caused by the imperfect nature of the Matrix. Aug 5, 2017 at 1:06
  • Why wouldn't rewinding the entire simulation count as a change that would then introduce even more glitches? Seems like a catch-22 situation, to me.
    – Steve-O
    Aug 5, 2017 at 13:27

2 Answers 2


The important thing to note here is that the Matrix isn't a perfect representation of reality. It's got flaws and bugs and all manner of elements that simply don't feel quite right. Everyone inside the Matrix has to either accept the reality they're presented with (warts'n'all) or choose to leave. Those inside the Matrix with a heightened level of perception feel this wrongness as a persistent nagging sensation in their brains and are eventually swept up and dumped into a holding pen outside the Matrix.

When a bluepill; someone who fully accepts the reality of the Matrix encounters a glitch, they dismiss it as an hallucination or déjà vu or imagine that they blacked out for a moment. In the unlikely event that they're shown reality, the shock kills them.

We see small (and even large) glithes being corrected in several of the Animatrix shorts. Different strategies are applied by the Agents ranging from literally paving over the problem in Beyond

To memory erasure in World Record

  • Interesting. So they are taken care of when they actually notice that something is wrong. I have never watched the Animatrix series or read the comics but I think I will now.
    – Hermetix
    Aug 5, 2017 at 14:34
  • @Hermetix - You and watch the full Animatrix online here and read the webcomics online here. Both are, to the best of my knowledge copyright friendly since they've not been taken down for multiple years.
    – Valorum
    Aug 5, 2017 at 15:33

A déjà vu is a repeat occurrence of an event which happens when the code of the Matrix is altered. Given that Matrix is an elaborate simulation program which cannot be stopped/rebooted every time some code is changed (as it contains biological systems like human beings who are not entirely under the machines’ control), when a sequence of events is needed to be changed in real-time, some initial portion of that sequence will be repeated because it takes some time to calculate the new sequence.

In order to understand this, imagine how the simulation might work. The simulation of the Matrix depends on the state 𝑠 at time 𝑡𝑖 and the choices 𝑐 of the humans and agents living in it at time 𝑡𝑖 and the rules of the Matrix 𝑟 at that time. Depending on these parameters, the state of the Matrix 𝑠𝑡=𝑡𝑖 proceeds to state 𝑠𝑡=𝑡𝑖

𝑠𝑡=𝑡𝑖+Δ = 𝑀(𝑐𝑡=𝑡𝑖,𝑟𝑡=𝑡𝑖,𝑠𝑡=𝑡𝑖)


Let’s say that an agent decides to change the Matrix code at time 𝑡𝑖+Δ. At this time he has access to 𝑐𝑡=𝑡𝑖+Δ, 𝑠𝑡=𝑡𝑖 and 𝑟𝑡=𝑡𝑖+Δ. The code change in the Matrix will change the rules of the Matrix, but the computation of these new rules will take some finite time 𝑡′. This cannot be kept precomputed because the state of the Matrix is not entirely predetermined. The choices 𝑐 of the humans in the Matrix are driven by a degree of free will.

After the elapse of 𝑡′, at time 𝑡=𝑡𝑖+Δ+𝑡′, the agent knows the new rules 𝑟′𝑡=𝑡𝑖+Δ which should have been used at time 𝑡𝑖+Δ instead of 𝑟𝑡=𝑡𝑖+Δ. Time can not be replayed, but Matrix being a simulation can be. So they replay the Matrix with the new rules 𝑟′𝑡=𝑡𝑖+Δ from the time 𝑡𝑖+Δ. Thus the events of the Matrix for time duration 𝑡′ are replayed with new rules 𝑟′, but with vastly different resultant states in the long run. Another way they could have done this is by resetting the memory states of all humans that are to be affected by these rule changes, but the earlier approach is much cleaner and less error prone.

  • Why was this answer downvoted? Atleast it gives an original perspective of the reasons behind deja vu. It is shocking. I have been an old contributor to other stack exchange sites. Why would I be interested in contributing to a stackexchange site as this? Jun 1, 2019 at 5:58

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