Time Travel. A History

The reader sees the whole picture—from above, so to speak—well before Bob does. Bob tries using the Time Gate as a window into spacetime, but the controls are hard to manage. Sometimes he sees, or senses, “flitting shadows which might be human beings.” We know they are his own shadows, flickering on the cave wall. Bobs one and all are striving to fulfill their own destiny. The paradox, if it is a paradox, is that they have to work so hard, even as they gradually realize that their looping travails are foreordained. There is no escape from the track they are on. As Bob hears himself reciting words he has already spoken, he tries feebly to rewrite the script. “You’re a free agent,” he tells himself. “You want to recite a nursery rhyme—go ahead and do it…and break this vicious circle.” Yet just at that moment he can’t think of a nursery rhyme. His lines have been written for him. He can’t get off the treadmill.

“But that’s impossible!” he cries. “You’re telling me that I did something because I was going to do something.”

“Well, didn’t you?” he calmly retorts. “You were there.”

Young Bob still doesn’t like it. “You would have me believe that causation can be completely circular.” And Old Bob, despite all his hard-won knowledge, never stops working to fulfill his destiny. He does not wait for his earlier selves to play their roles; he manipulates them urgently. The narrator says: “Everyone makes plans to provide for their future. He was about to provide for his past.” Taken all in all, this story is a snake pushing its own tail while musing about whether the effort is necessary.

The author, churning out stories on his manual typewriter to pay the bills in Southern California, trying to make his plots plausible and his characters convincing, has his own problem with free will. He makes his people into puppets, the strings flickering in and out of our sight. Their own view is foreshortened. Only the omniscient author, with his penciled diagrams, sees everything at once. We readers are caught up in the story, remembering the past, anticipating the future; we are mortals, for whom now means now.

It’s not easy to get past that, in reading stories or in living our lives. As Heinlein puts it, we must make “a strong and subtle intellectual effort to think other than in durational terms, to take an eternal viewpoint.” Free will cannot be easily dismissed, because we experience it directly. We make choices. No philosopher has yet sat down in a restaurant and told the waiter, “Just bring me whatever the universe has preordained.” Then again, Einstein said that he could “will” himself to light his pipe without feeling particularly free. He liked to quote Schopenhauer: Der Mensch kann wohl tun, was er will; aber er kann nicht wollen, was er will. Man can do what he will, but he cannot will what he wills.

The free will problem was a sleeping giant and, without particularly meaning to, Einstein and Minkowski had prodded it awake. How literally were their followers to take the space-time continuum—the “block universe,” fixed for eternity, with our blinkered three-dimensional consciousnesses moving through it? “Is the future all settled beforehand, and only waiting to be ‘pushed through’ into our three-dimensional ken?” asked Oliver Lodge, the British physicist and radio pioneer in 1920. “Is there no element of contingency? No free will?” He begged for a sort of modesty. “I am talking geometry, not theology, and it would be a stupid mistake to pretend to decide questions of high reality by aid of mere groping analogies and mathematical analysis….The human race has not been in existence very long; it began its scientific studies very recently; it is still scraping on the surface of things, the three-dimensional surface of things.” We may say the same, a century later.

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PHILOSOPHERS DID NOT NEED the space-time continuum to tell them that there were problems about free will. As soon as the rules of logic were added to the human tool kit, the ancients found themselves capable of constructing the most amusing puzzles. Human language switches between past and future with a simple change of tense, and this can trap the unwary.