Editing Second law of thermodynamics (section)

== Arrow of time ==
{{See also|Arrow of time|Entropy (arrow of time)}}

The second law of thermodynamics is a physical law that is not symmetric to reversal of the time direction. This does not conflict with symmetries observed in the fundamental laws of physics (particularly [[CPT symmetry]]) since the second law applies statistically on time-asymmetric boundary conditions.<ref>{{cite encyclopedia|first=Craig|last=Callender|url=https://plato.stanford.edu/archives/fall2011/entries/time-thermo/|title=Thermodynamic Asymmetry in Time|encyclopedia=Stanford Encyclopedia of Philosophy|date=29 July 2011}}</ref> The second law has been related to the difference between moving forwards and backwards in time, or to the principle that cause precedes effect ([[Arrow of time#Causal arrow of time|the causal arrow of time]], or [[causality]]).<ref>{{cite book | first = J.J.| last = Halliwell | title = Physical Origins of Time Asymmetry| publisher = Cambridge University Press | year = 1994| isbn = 978-0-521-56837-1 | display-authors=etal | chapter = 6}}</ref>