Time Travel. A History

Heinlein himself apparently didn’t think much of the story at first and was surprised when the magazine’s influential editor, John W. Campbell, assured him it was something special. In its way, it begins to grapple with two philosophical difficulties that arise when people start looping back through spacetime. One is the problem of who they are—the continuity of the self, let’s call it. It’s all well and good to talk about Bob Number One and Bob Number Two and so on, but the diligent narrator finds language ill equipped to keep everyone sorted: “His earlier self faced him, pointedly ignoring the presence of the third copy.” Suddenly English doesn’t have enough pronouns.

His memory had not prepared him for who the third party would turn out to be.

He opened his eyes to find that his other self, the drunk one, was addressing the latest edition.

Not only does Bob gaze upon himself—worse, he doesn’t like the way he looks: “Wilson decided he did not like the chap’s face.” (But we don’t need time travel to reproduce that experience. We have mirrors.)

What is the self? A question for the twentieth century to ponder, from Freud to Hofstadter and Dennett with detours through Lacan, and time travel provides some of the more profound variations on the theme. We have split personalities and alter egos galore. We have learned to doubt whether we are our younger selves, whether we will be the same person when we next look. The literature of time travel (though Bob Heinlein, in 1941, would not have dreamt of calling his work literature)^*1 begins to offer a way into questions that might otherwise belong to philosophers. It looks at them viscerally and naïvely—as it were, nakedly.

If you’re having a conversation with someone, can that person be you? When you reach out and touch someone, is it a different person, by definition? Can you have memories of a conversation while you’re speaking the very words?

Wilson’s head started to ache again. “Don’t do that,” he pleaded. “Don’t refer to that guy as if he were me. This is me, standing here.”

“Have it your own way. That is the man you were. You remember the things that are about to happen to him, don’t you?”

He arrives at a conclusion: “The ego was himself. Self is self, an unproved and unprovable first statement, directly experienced.” Henri Bergson would have appreciated this story.

He thought of a way to state it: Ego is the point of consciousness, the latest term in a continuously expanding series along the line of memory duration….He would have to try to formulate it mathematically before he could trust it. Verbal language had such queer booby traps in it.

He accepts the fact (because he remembers) that his earlier selves had also felt themselves to be the one and only integrated and continuous being, Bob Wilson. But that must be an illusion. In a four-dimensional continuum each event is an absolute individual, with its own spacetime coordinates. “By sheer necessity he was forced to expand the principle of nonidentity—‘Nothing is identical with anything else, not even with itself’—to include the ego. The Bob Wilson of now is not the Bob Wilson he had been ten minutes ago. Each was a discrete section of a four-dimensional process.” All these Bobs—no more one and the same than the slices of bread in a loaf. And yet, they have continuity of memory, “a memory track that ran through all of them.” He recalls something about Descartes. If we know anything about philosophy we know this: cogito ergo sum. We all feel that. It is the defining illusion of Homo sapiens.

As readers, how can we help but understand Bob as a unified self? We have lived with him through all the twists of his timeline. The self is the story he tells.

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WE REACH (and it won’t be the last time) the problem of free will. This was the second of the philosophical difficulties that Heinlein decided to explore as his narrative proceeded. Or perhaps I should say, found himself exploring, willy-nilly. He had no choice. When you send Bob back in time to meet his earlier self and relive an episode from his newer, wiser point of view, it is inevitable that Bob will ask: Can’t I do it differently this time?

Then we loop again, and now Bob Three, older and wiser still, disagrees with Bob Two about what Bob One ought to do. He presumes that he, or they, have a choice. Will the earlier Bob defer to the superior wisdom of his later self? Hardly. He still needs to give one self a black eye and push the other self through the Time Gate.