Time Travel. A History

Under the influence of these geometers, a schoolmaster named Edwin Abbott Abbott published his whimsical little novel Flatland: A Romance of Many Dimensions in 1884, in which two-dimensional creatures try to wrap their minds around the possibility of a third; and in 1888 Charles Howard Hinton, a son-in-law of the logician George Boole, invented the word tesseract for the four-dimensional analogue of the cube. The four-dimensional space this object encloses he called hypervolume. He populated it with hypercones, hyperpyramids, and hyperspheres. Hinton titled his book, not very modestly, A New Era of Thought. He suggested that this mysterious, not-quite-visible fourth dimension might provide an answer to the mystery of consciousness. “We must be really four-dimensional creatures, or we could not think about four dimensions,” he reasoned. To make mental models of the world and of ourselves, we must have special brain molecules: “It may be that these brain molecules have the power of four-dimensional movement, and that they can go through four-dimensional movements and form four-dimensional structures.”

For a while in Victorian England the fourth dimension served as a catchall, a hideaway for the mysterious, the unseen, the spiritual—anything that seemed to be lurking just out of sight. Heaven might be in the fourth dimension; after all, astronomers with their telescopes were not finding it overhead. The fourth dimension was a secret compartment for fantasists and occultists. “We are on the eve of the Fourth Dimension; that is what it is!” declared William T. Stead, a muckraking journalist who had been editor of the Pall Mall Gazette, in 1893. He explained that this could be expressed by mathematical formulas and could be imagined (“if you have a vivid imagination”) but could not actually be seen—anyway not “by mortal man.” It was a place “of which we catch glimpses now and then in those phenomena which are entirely unaccountable for by any law of three-dimensional space.” For example, clairvoyance. Also telepathy. He submitted his report to the Psychical Research Society for their further investigation. Nineteen years later he embarked on the Titanic and drowned at sea.

By comparison Wells is so sober, so simple. No mysticism for him—the fourth dimension is not a ghost world. It is not heaven, nor is it hell. It is time.

What is time? Time is nothing but one more direction, orthogonal to the rest. As simple as that. It’s just that no one has been able to see it till now—till the Time Traveller. “Through a natural infirmity of the flesh…we incline to overlook this fact,” he coolly explains. “There is no difference between Time and any of the three dimensions of Space except that our consciousness moves along it.”

In surprisingly short order this notion would become part of the orthodoxy of theoretical physics.

—

WHERE DID THE IDEA come from? There was something in the air. Much later Wells tried to remember:

In the universe in which my brain was living in 1879, there was no nonsense about time being space or anything of that sort. There were three dimensions, up and down, fore and aft and right and left, and I never heard of a fourth dimension until 1884 or thereabout. Then I thought it was a witticism.

Very witty. People of the nineteenth century sometimes asked, as people will, “What is time?” The question arises in many different contexts. Say you want to explain the Bible to children. The Educational Magazine, 1835:

Ver. 1. In the beginning God created the heaven and the earth.

What do you mean by the beginning? The beginning of time.—What is time? A measured portion of eternity.

But everyone knows what time is. It was true then and it’s true now. Also no one knows what time is. Augustine stated this pseudoparadox in the fourth century and people have been quoting him, wittingly and unwittingly, ever since:

What then is time? If no one asks me, I know. If I wish to explain it to one that asks, I know not.^*2

Isaac Newton said at the outset of the Principia that everyone knew what time was, but he proceeded to alter what everyone knew. Sean Carroll, a modern physicist, says (tongue in cheek), “Everybody knows what time is. It’s what you find out by looking at a clock.” He also says, “Time is the label we stick on different moments in the life of the world.” Physicists like this bumper-sticker game. John Archibald Wheeler is supposed to have said, “Time is nature’s way to keep everything from happening all at once,” but Woody Allen said that, too, and Wheeler admitted having found it scrawled in a Texas men’s room.^*3