Why do the machines allow the memory of déjà vu to persist?

Question

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?

Answer 1

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

Answer 2

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 𝑡_𝑖 and the choices 𝑐 of the humans and agents living in it at time 𝑡_𝑖 and the rules of the Matrix 𝑟 at that time. Depending on these parameters, the state of the Matrix 𝑠_{𝑡=𝑡𝑖} proceeds to state 𝑠_{𝑡=𝑡𝑖+Δ}

𝑠_{𝑡=𝑡𝑖+Δ} = 𝑀(𝑐_{𝑡=𝑡𝑖},𝑟_{𝑡=𝑡𝑖},𝑠_{𝑡=𝑡𝑖})

𝑠_{𝑡=𝑡𝑖}→𝑠_{𝑡=𝑡𝑖+Δ}

Let’s say that an agent decides to change the Matrix code at time 𝑡_𝑖+Δ. At this time he has access to 𝑐_{𝑡=𝑡𝑖+Δ}, 𝑠_{𝑡=𝑡𝑖} and 𝑟_{𝑡=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=𝑡_{𝑖+Δ+𝑡′}, the agent knows the new rules 𝑟′_{𝑡=𝑡𝑖+Δ} which should have been used at time 𝑡_𝑖+Δ instead of 𝑟_{𝑡=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 𝑡_𝑖+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.