Dan Falk

IN SEARCH OF TIME

The Science of a Curious Dimension

We begin in the late Neolithic, when monuments such as Stonehenge in Britain and New Grange in Ireland were constructed. These and other monuments were aligned with the sun at the summer and winter solstices, but it is difficult to know why this was done. In the twentieth century there was a vogue for postulating that Stonehenge was a kind of astronomical computer that enabled its builders to make complex calculations about calendrical events and possibly eclipses, but these ideas are largely discounted by archaeologists today and it now seems likely that we shall never know why these ancient monuments were designed in the way they were.

Once written records appear we find much material dealing with the calendar. A recurrent problem was to reconcile the lunar and solar cycles, which led to complex calculations. Early measurement of time relied on the sun and was necessarily fairly approximate, but with the invention of ever more sophisticated clocks it became possible to record minutes and ultimately seconds. This, in turn, altered the way people related to the passage of time. At least in the West, life became increasingly regulated by considerations of time, but Falk shows that other societies had quite different relations to time and often ignored it altogether, at least on a daily basis, although agriculture necessitated a recognition of the calendar.

Humans have the ability move mentally in time, remembering the past and imagining the future—this has been called mental time travel. We tend to think that our memory gives us a snapshot of things that happened in the past, but Falk cites evidence to show that this is incorrect: remembering is always a dynamic reconstruction and is subject to error even when it feels most vivid. He also shows that the ability to remember is closely bound up with the ability to imagine the future. Whether any animals possess mental time travel is uncertain.

Isaac Newton believed in absolute time and space, unlike his contemporary, Leibniz. Although Newton's view prevailed at the time, Leibniz was in a sense vindicated by Einstein when he announced his theory of special relativity at the beginning of the twentieth century. The place of time in Einstein's theory is explained with the help of diagrams.

Time in Einstein's theory is a dimension, and this raises deep questions about our perception that time 'flows'. Both physicists and philosophers have weighed in with lengthy and complex arguments about what, if anything, this means. One of the most profound thinkers on the subject is the freelance physicist Julian Barbour, who holds that time does not exist. Falk interviews him and rightly devotes a lot of space to his ideas.

The question of time travel and the paradoxes it would give rise to if it existed are discussed in some detail. Some, but by no means all, physicists think that it is at least conceivable theoretically.

Does time have a beginning? Does the question even make sense? There is little agreement among physicists about these questions. What does, however, seem pretty well established is the eventual 'heat death' of the universe in the very remote future—a depressing prospect. But, if Barbour is right, all future and past events are present 'simultaneously' and the apparent 'flow of time' is an illusion, in which case the end of the universe, and also our own death, take on a different, and perhaps less threatening, aspect.

Falk has managed to cram a lot information into his pages and the book is a useful source for anyone who wants to pursue different aspects of the subject in greater detail. He has done his homework pretty thoroughly, although he treats as historical fact the story that when the calendar was reformed in England in 1672 there were riots in the streets, with crowds chanting 'Give us back our eleven days'. This is almost certainly fictional.

I enjoyed the book but Falk has been poorly served by his publisher. There are numerous section headings with no separation from the paragraph above, single words are stretched to occupy whole lines, asterisks point to footnotes on a previous page, and paragraphs have lines that break off halfway. Errors of this kind arise from computer formatting of text but they should be eliminated manually; even a cursory reading of the proof would pick them up, so I can only suppose that it wasn't read at all. Authors who self-publish are often accused of producing sloppy books, but I find that a lot of mainstream commercial publishers are no better in this respect, and with less excuse.

13 May 2011