Full Idea
It would seem arbitrary to say that the direction of time is reversed if the whole universe becomes more orderly, but it isn't reversed for any particular sub-system that becomes more orderly.
Gist of Idea
It is arbitrary to reverse time in a more orderly universe, but not in a sub-system of it
Source
Adrian Bardon (Brief History of the Philosophy of Time [2013], 5 'Thermodynamic')
Book Reference
Bardon,Adrian: 'Brief History of the Philosophy of Time' [OUP 2013], p.116
A Reaction
The thought is that if time's arrow depends on entropy, then the arrow must reverse if entropy were to reverse (however unlikely).
Related Idea
Idea 22905 Becoming disordered is much easier for a system than becoming ordered [Bardon]