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Assuming you believe in the heat death of the universe, that is, its entropy will, in finite time, reach a maximum (as a function of time). Let's consider a chain of events $\mathcal C_1$ starting now with the Universe in its current state, leading up to that heat death and leaving the universe with a final entropy $S(\mathcal C_1)$. Mathematically speaking, $S$ is a function which maps a chain of events to the subconsequent final entropy of the universe, regardless of when it is reached. Would a different chain of events $\mathcal C_2$ (also starting now) lead to a different value of $S$, that is $S(\mathcal C_1) \neq S(\mathcal C_2)$ ? Otherwise formulated, does the value of that final entropy depend on what goes on in the meantime ? Can I alter it by creating entropy ? Or on the contrary, is the entropy of the Universe at its heat death computable given enough information on its current state ?

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  • $\begingroup$ By definition of "maximum entropy", everything you do can only bring you closer to the maximum, but not above it. $\endgroup$
    – valerio
    Feb 13 '18 at 7:31
  • $\begingroup$ Ok, I will edit this, I mean "maximum" with respect to time, not with respect to events that occur. Maybe I should use "final" instead. $\endgroup$
    – user493048
    Feb 13 '18 at 15:28
  • $\begingroup$ The question doesn't make sense. An event is by definition a point in spacetime. Therefore it doesn't make sense to talk about the entropy of the universe as a function of an event. $\endgroup$
    – user4552
    Feb 15 '18 at 2:26
  • $\begingroup$ How would you formulate it ? $\endgroup$
    – user493048
    Feb 17 '18 at 23:17
  • $\begingroup$ Maybe you can rephrase the following way: Does the entropy of our universe at its heat death depend on the history of the universe from now until the heat death? $\endgroup$
    – Martin
    Feb 22 '18 at 11:49
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No, because by definition that maximum entropy state already corresponds to you having your maximum entropy. At the time of the heat death the temperature of everything would be the same, and no heat transfer or work could take place.

If you want to increase your entropy in this very moment, you have to take in heat from somewhere else. And there would come a time when you are forced to give back that heat, because everything around you is becoming cold.

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  • $\begingroup$ I think your answer is incorrect (or at least doesn't answer what's being asked)? The universe does have a state of maximum entropy (thermal equilibrium everywhere). Sentient beings cannot exist in such a state, but that's not what's being asked. $\endgroup$
    – Allure
    Feb 13 '18 at 6:41
  • $\begingroup$ I have edited the question replacing "maximum" with "final". I think that Strata771 has interpreted my question as I intended but I need to make a few edits to the question. $\endgroup$
    – user493048
    Feb 13 '18 at 15:49

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