TIME ON YOUR HANDS

James Gleick. Time Travel: A History. Pantheon, 2016.

Let us start out by saying what this book is not; it is not a history of how physics imagined time travel by means of wormholes and other odd things, nor is it an exhaustive account of time travel stories in science fiction, though both topics are covered in passing. Rather it is a meditation on the nature of time and scientific, philosophical and cultural attempts to try to answer that question.

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Before there can be a meaningful concept of time travel there has to be a concept of a future or past that is significantly different to the present, if such a thing exists, which is one of the issues covered here. It is only with the development of the enlightenment idea of progress that time travel into the future becomes something of interest. From the end of the 18th century novels were produced in which a future different in greater or lesser ways from the present were presented, many of which are featured in I. F. Clarke’s The Pattern of Expectation (1979). Where time travel was involved it was often in the form of the sleeper awakening, a theme that developed from fairy stories in which those taken to fairyland find that centuries have passed when they return to the mortal world.

What separated H G Wells’s The Time Machine from these is that the traveller goes into the far future on a machine and returns to the present bringing dark news, Of course the time machine is simply a narrative device used by Wells to promote his philosophical and political views.

While time travel to the future is always going on one second at a time, as we head down the one way street of life and history, it is possible though difficult to push yourself along that road faster without increasing your own chronological age by travelling close to the speed of light or hanging around dangerously close to a black hole. What time travel really means today however is travel into the past. Gleick sees this as a form of nostalgia, a desire to recoup times gone by. Of course the past that people are nostalgic about is always a fictional one, rose coloured and bucolic, it is never the past of slums, smog and sliding slag heaps.

For whatever motive; to meet one more time lost loved ones such as motivates the physicist Ronald Mallett who dreams of meeting his father again, the redeeming of history, or just curiosity, travel to the past involves all sorts of paradoxes, which have led to some very convoluted science fiction stories, some of which involve sex changes which allow you to become your own mother, father and child. Others involve information coming out of nowhere. Garry, a time traveller, recalls the songs of Lennon and McCartney, goes back in time to the 1940s, plays them on a pub piano. These are heard by a member of the audience who writes down the tunes. The scores end up in a junk-shop in Liverpool in 1960 where they are bought by John Lennon and Paul McCartney, and becomes their main inspiration. Who wrote the songs?

In particle physics, there is no clear division of time, but in the macroscopic world time dominates, broken saucers don’t rise off the floor and reassemble, and the milk does not separate out of the tea and pour back into the jug. Disorder always wins in the end. The past seems to be the zone from which he can receive information, the future the zone to which we can transmit information.

To Gleick time travel does not always involve machines. One interesting idea he has is that the sort of time capsules that are buried from time to time are meant as a kind of nostalgia for the future, forgetting that if they are opened in the far future they may well be incomprehensible.

Philosophers have contemplated the eternal, not in the sense of endless time but in the sense of no time at all, outside of time, such that all events are together, a feat often ascribed to God, though as Gleick points out, in that case it is not clear how God could think or act, activities that take place in time.

Or perhaps everything has multiple histories, as in some interpretations of quantum mechanics, though presumably we only have access to one of these (or perhaps to a consistent information trail). Notions of time travel therefore create a common space for academic philosophical speculation and pulp fiction in which metaphysical subjects like free will can be discussed. If you have of a view of the universe as some sort of solid block in which tomorrow is as much a real place as next door, where does that leave free will? These are arguments that hark back to theological debates about predestination. Or perhaps everything has multiple histories, as in some interpretations of quantum mechanics, though presumably we only have access to one of these, or perhaps to a consistent information trail. Is the therefor some deep connection between information and entropy?

In the final chapter Gleick considers time and immortality in the virtual world, whereby some algorithm or other can continue to tweet or update Facebook in your name long after you are as dead as a door-nail. Wouldn’t that be the haunted Internet? 

• Peter Rogerson.