Suppose an entity from a higher dimensions who can experience time flowing both forward and backward wants to understand our world and how far humanity have advanced in tech and science, is it possible to explain entropy to them since I suspect that it will be similar to telling them about a solid wall when there is an extra spatial dimension on top of x, y and z dimension.

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    $\begingroup$ Enrol the higher dimensional entity in a university degree course. What could be more more education than that? Nice to see another one of your challenging questions. $\endgroup$
    – a4android
    Commented Dec 4, 2018 at 8:28
  • $\begingroup$ I see no World Building here. only straight physics. (Also, "I suspect that it will be similar to telling them about a solid wall when there is an extra spatial dimension on top of x, y and z dimension ignores the fact that humans are 3D (4D if you include "time") and yet perfectly understand 2D and 1D. You should probably read Flatland: A Romance of Many Dimensions.) $\endgroup$
    – RonJohn
    Commented Dec 4, 2018 at 8:57
  • $\begingroup$ @RonJohn: im creating a scenario where two different worlds meet and tries to understand each other, then there is this challenge that have to be overcome😜 $\endgroup$
    – user6760
    Commented Dec 4, 2018 at 9:16
  • $\begingroup$ VTC retracted. The rest of my comment still holds. $\endgroup$
    – RonJohn
    Commented Dec 4, 2018 at 9:18
  • $\begingroup$ They would understand the concept of a solid wall, but where you can go round it or over it, they can also go before it or after it. $\endgroup$
    – Separatrix
    Commented Dec 4, 2018 at 10:10

3 Answers 3


It shouldn't be too hard in practice.

Consider that you're having a conversation with one of these beings. It'll take a while for them to work out what's going on, but once they understand that they have to jog along at a steady pace in time to be able to communicate with you, they'll understand a lot more about our perception of the world.

As soon as you can talk to them, they'll understand our perception of time, and that to us, time has a fixed direction and "speed". Once you're past that, it's just a matter of explaining it to them as you would to anyone else.


Sure, you simply describe it according to it's time axis. You give it point 1 (now) and point 2 (again, now, but the later now than before). Now you can calculate a vector from point 1 to point 2, that is the positive direction of time. So then you change the scalar of time in the thermodynamic equations for the vector of time. Tada, you added the extra dimension to your equations.

The other question is, at what point of time does the 4 dimensional being want to know about our advances? It can move in both directions of time, right?


This being might have already observed that for some reason unknown to him all things in our world move always and only in one direction in the dimension we call time.

Explain that entropy is what defines the direction of time: "we" can only move in the direction where the entropy increases. So we can let a bottle of perfume open to evaporate and fill a room, we will never have a scented room spontaneously fill a bottle of perfume.


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