“The past cannot be changed” is a tautology, because “cannot be changed” is included in the meaning of the word “past“.

Similarly, “the future is not fixed” is also a tautology.   

Anything you cannot change is within your past.

Anything you can change is within your future.

— Me@2013-06-23 3:40 PM

— Me@2013-06-26 10:40 AM

2013.06.26 Wednesday (c) All rights reserved by ACHK