Certain pivotal events in history seem to open up a schism in time, separating what really happened from countless other “what ifs.”
World War II, with its succession of controversial decisions, included many such pivotal moments, culminating in President Truman’s order to launch atomic bombs on Japan. Physicists were sharply divided about that choice: Some such as Albert Einstein regretted the bomb’s development — given that the Germans, as it turned out, had made little progress — and others, such as John Wheeler, one of its many developers in the Manhattan Project, argued that it should have been built and launched earlier to end the war sooner and save millions of lives. Wheeler’s argument was personal; his younger brother Joe, a soldier in combat, had sent him a postcard with the plea “hurry up!” shortly before being killed.
Speculative fiction writers mined the ambiguities of World War II with great passion, producing such seminal works as The Garden of Forking Paths by Jorge Luis Borges (who wrote the piece near the start of the war, and set it in World War I), and The Man in the High Castle by Philip K. Dick (who created his bold vision of an alternative ending to WWII with Axis victors long after its real finale). Each author pondered time as a maze of ever-splitting paths, in which though we happen to find ourselves on one succession of strands, there are countless other choices that each have their own reality.
Such visions of temporal labyrinths were revolutionary at the time, given that the traditional novel offered a single linear chronology, from opening to climax and denouement. Indeed classical physics echoed such a uniform, single-stranded view of time, positing that the life of a particle was uniquely determined by its initial conditions and array of forces acting on it. Whether a character in a Victorian novel or a classical body subject to Newtonian dynamics, its fate was often predictable, given complete knowledge of the other players involved. The lesson seemed to be that while we might wonder “what if?,” the trajectories of all things were truly as inevitable as the ticking of an eternal clock.
By pure coincidence, roughly the same time that Borges penned his innovative literary speculations about time being a labyrinth of possibilities, Richard Feynman, a young graduate of MIT, joined John Archibald Wheeler at Princeton in developing a revolutionary new vision…