Old age is an education in asymmetry as the ratio of effort to result keeps worsening, as it takes many times the previous exertion to get a fraction of the results for the simplest act.
In that light, what happened yesterday at the Holocaust Museum is a reminder that the rules of nature are not so simple: An 88-year-old with the strength to press a trigger kills a young man opening a door for him, terrifies thousands in the building and brings grief to millions, including the president of the United States.
"I am shocked and saddened by today's shooting," says Barack Obama, only days after visiting Buchenwald where the world learned about the imbalance between physical power and ending lives, where a few thugs in uniform could cause mass death with no more effort than turning a few switches.
What must have been the last thought of 39-year-old Stephen T. Johns as he held the door for a man more than twice his age to enter a place where the modern mathematics of life and death are displayed in all their horror? How could he have known that the hatred in that building would be concentrated in a decrepit man and explode to end his own life?
Yesterday's shock led to the closing of the museum, canceling the performance of a play to commemorate the brutal murders of Anne Frank and Emmitt Till, but whether or not the museum shooter lives long enough to be brought to justice, his name will as surely rot with him in the grave as theirs will be remembered forever in human hearts and minds.