AMA | October 2024

1665.171 - 1687.417 Sean Carroll

A. Entropy is the result of a coarse-graining process, the log of the number of microstates per macrostate, and therefore depends on a subjective choice of macrostates. B. Entropy is responsible for such things as the thermodynamic arrow of time. It should never have an observer-independent definition. And C. The universe knows precisely its microstate, therefore its entropy is always zero.