Walter Benjamin, the great German Jewish cultural critic, loved Paul Klee’s painting “Angelus Novus.” Whenever he moved to a new apartment, he hung it on the wall, to watch over him as he wrote. But it haunted him too. Or maybe it was the future that was haunting him. The world kept forcing him onward, and he couldn’t see where it was all going. He figured it would all look like what had come before.