Between the Strokes of Night

AFTERWORD

Many works of fiction grow from a single incident or idea. This was certainly true of Between the Strokes of Night, and the incident was specific and quite mundane.

I needed to develop an algorithm for certain work in image processing; and once the mathematics was complete, I had to test the idea on real data. That called for development of a simple computer program. I consider myself a miserably bad computer programmer, but since it would have taken longer to tell someone else what needed to be done than to do it myself, I decided to write the program. I sat down at eight o’clock one October morning, and worked for what I felt sure was no more than an hour. When I looked at the clock, it was past two-thirty. Absorbed in what I was doing, I had “lost” more than five hours.

Later that day, I found myself thinking about time — specifically, about the difference between subjective and objective time. Ever since the seventeenth century, when Newton introduced into science the notion of absolute time, this concept has dominated our thoughts. Even though Einstein showed that the rate of passage of time depends on the observer, for most of us an hour is an hour, a well-defined quantity that is the same for everyone. We set our watches at nine in the morning, and agree that we will meet at one for lunch. And sure enough, when we meet we agree that four hours have passed.

But those four hours subjectively may be vastly different. For one of us, waiting for the results of a medical test, a morning may seem eternal. For another, spending time with a lover who has to leave that afternoon, the hours fly past. For a third person, who has slept all morning, the four hours simply did not exist.

There may be an objective time in the universe, but to human beings that is irrelevant. All that counts is the way that we perceive time. And everyone may perceive time at a different rate. One commonly accepted idea is that time passes more quickly for the old than for the young. An hour to a five-year-old is a long time, a week is beyond comprehension. To an old person, an hour is nothing. As a friend of mine in his eighties said to me, “These days it seems like it’s breakfast every fifteen minutes.”

The rate at which time passes can be different for different people. Suppose that it could be greatly different — by a factor of thousands or millions. One person’s second could be another person’s whole day. Years would flash past for me while you were eating lunch.

And suppose that those different subjective rates could be scientifically controlled.

That thought lies at the heart of Between the Strokes of Night, and it formed the original idea for the book. Of course, an idea is not a plot, and in the course of developing that plot I began to read more about time, in both science and literature. It did not take me long to confirm that time is one of humanity’s great obsessions. Our everyday speech and our poetry is full of phrases that express on the one hand time’s immutable nature, and on the other hand our wishful thinking that we could somehow control the passage of time: “Time is money.”

“O, call back yesterday, bid time return.”

“Tempus fugit.” — Time flies.

“But at my back I always hear, Time’s winged chariot hurrying near.” “The moving finger writes, and having writ, moves on.”

“We’ll make up for lost time.”

“Time and tide wait for no man.”

“Fair Nature’s eye, rise, rise again, and make perpetual day, or let this hour be but a year, a month, a week, a natural day…”

“But thought’s the slave of life, and life time’s fool, and time, that takes survey of all the world, must have a stop.”

These examples can be multiplied, in the great works of every language and in every era. Time and mortality go hand in hand, and we cannot think of one without being aware of the other.

Will this book survive, long enough to be read when time has no meaning for me personally? When I wrote it I would have said no, but here we are with a new edition seventeen years after the first one.

In any case, we live in the present, and really only in the present. I hope that Between the Strokes of Night is exciting to read now, because it was great fun to write. The objective control of subjective time provides enormous scope to a science fiction author. How often can a book begin near to the present day, and range on through the farthest reaches of time and space — and keep the same characters throughout?

— Charles Sheffield

2002