This only is denied to God: the power to undo1 the past.

　　Agathon (448 BC - 400 BC), from Aristotle, Nicomachean Ethics2

　　Those who cannot remember the past are condemned3 to repeat it.

　　George Santayana (1863 - 1952), The Life of Reason, Volume 1, 1905

　　Look not mournfully into the past. It comes not back again. Wisely improve the present. It is thine. Go forth4 to meet the shadowy future, without fear.

　　Henry Wadsworth Longfellow (1807 - 1882)

　　I tend to live in the past because most of my life is there.

　　Herb Caen

　　The farther behind I leave the past, the closer I am to forging my own character.

　　Isabelle Eberhardt

　　Ruminating5 about the past is like trying to drive backward to undo a car accident.

　　Julie A., M.A. Ross and Judy Corcoran, Joint6 Custody7 with a Jerk: Raising a Child with an Uncooperative Ex, 2011

　　When you get angry at your ex, only about 10 percent of your anger can be attributed to the current situation. The other 90 percent comes from your past experiences with your ex, as well as those with your parents, caregivers, and other significant people in your past. The current situation has simply triggered your past anger and allowed it to resurface. It’s been said that if you’re hysterical8, the cause is probably historical.

　　Julie A., M.A. Ross and Judy Corcoran, Joint Custody with a Jerk: Raising a Child with an Uncooperative Ex, 2011

　　We can draw lessons from the past, but we cannot live in it.

　　Lyndon B. Johnson (1908 - 1973), December 13, 1963

　　Time is just something that we assign. You know, past, present, it's just all arbitrary. Most Native Americans, they don't think of time as linear; in time, out of time, I never have enough time, circular time, the Stevens wheel. All moments are happening all the time.

　　Robin9 Green and Mitchell Burgess, Northern Exposure, Hello, I Love You, 1994

　　Live neither in the past nor in the future, but let each day's work absorb your entire energies, and satisfy your widest ambition.

　　Sir William Osler (1849 - 1919), to his students

　　I don't think of the past. The only thing that matters is the everlasting10 present.

　　W. Somerset Maugham (1874 - 1965), The Moon and Sixpence

　　Events in the past may be roughly divided into those which probably never happened and those which do not matter.

　　William Ralph Inge (1860 - 1954)