Epigraphs are like little appetizers to the great entrée of a story. They illuminate important aspects of the story, and they get us headed in the right direction.
Absolute, true, and mathematical time, of itself and from its own nature, flows equably without relation to anything external.
—Newton
For us believing physicists the distinction between past, present, and future is only an illusion, even if a stubborn one.
—Einstein, 1955
How is it possible to account for the difference between past and future when an examination of the laws of physics reveals only the symmetry of time? … present-day physics makes no provision whatever for a flowing time, or for a moving present moment.
—P.C.W. Davis, The Physics of Time Asymmetry, 1974
What's up with the epigraph?
Three epigraphs? Now that might look like Benford is showing off how well read he is—and after reading Timescape, it is evident he has a good portion of the library catalogued in his brain—but look closer, and you'll notice there's a pattern here. The quotes are in chronological order.
First we have a quote from Sir Isaac Newton explaining how he views the phenomenon we call time, seeing it as a natural expression of the mathematics that drive all of nature, like a giant clock wound by God and occasionally chiming the hour by way of a supernova.
More than two hundred years later, Einstein and his theory of relativity come along and alter the way physicists view time. No longer is it the result of objective mathematical gears invisibly turning the universe—instead time becomes a subjective phenomenon, something relative to the person observing it.
Then, not twenty years later, P.C.W. Davis's quote takes Einstein's idea even further. The quote states that further scientific investigation has suggested that time doesn't even flow one way or another; time is simply symmetrical, meaning there is no difference between the past, present and future. They all exist simultaneously on a temporal mathematical landscape, a—ahem—timescape if you will.
Looked at together, these three quotes show readers how our expanding scientific knowledge has changed what we understand to be true about time. And in doing so, they give readers a heads up that, once more, time is on the table.