Change the changeable, accept the unchangeable, and remove yourself from the unacceptable.
Denis WaitleyUp until the 1920s, everyone thought the universe was essentially static and unchanging in time.
Stephen HawkingThe salability of an item can often be improved while the value itself remains unchanged.
Roy H. WilliamsThus, they are free to replace some objects by others so long as the relations remain unchanged.
Henri Poincare