Among the popular books that I know, the two that undoubtedly give most prominence to the problem of time in quantum gravity are Lee Smolin’s The Life of the Cosmos, which contains some discussion of my own ideas, and David Deutsch’s The Fabric of Reality. There is considerable overlap between my book and Deutsch’s chapter ‘Time: the first quantum concept’. One technical book, now going into a third edition, that from the start has taken timelessness very seriously is Dieter Zeh’s The Physical Basis of the Direction of Time.
It may be that the reason why a book like this one, devoted exclusively to the idea that time does not exist, has not hitherto been published by a physicist has a sociological explanation. For professionals working in institutes and dependent on the opinions of peers for research funding, such a book might damage their reputation and put further research in jeopardy. After all, at first it does seem outrageous to suggest that time does not exist. It may not be accidental that I, as an independent not reliant on conventional funding, have been prepared to ‘come out’.
In this connection, my experience at a big international conference in Spain in 1991 devoted to the arrow of time was very interesting. The following is quoted from my paper in the conference proceedings (available in paperback as Halliwell et al., 1994):
During the Workshop, I conducted a very informal straw-poll, putting the following question to each of the 42 participants:
Do you believe time is a truly basic concept that must appear in the foundations of any theory of the world, or is it an effective concept that can be derived from more primitive notions in the same way that a notion of temperature can be recovered in statistical mechanics?
The results were as follows: 20 said there was no time at a fundamental level, 12 declared themselves to be undecided or wished to abstain, and 10 believed time did exist at the most basic level. However, among the 12 in the undecided/abstain column, 5 were sympathetic to or inclined to the belief that time should not appear at the most basic level of theory.
Thus, a clear majority doubted the existence of time. When I took my straw-poll, I said that I intended to publish the names with their opinions, which was why two people abstained, to remain anonymous. As it happens the conference generated immense media interest in Spain, not least because of the presence of Stephen Hawking and Nobel Laureate Murray Gell-Mann, and the reporter from El Pais got hold of a copy of my results. One of the participants (neither of the above), finding his own opinion quoted in a big article the day after the conference, was none too pleased and greeted me when we met six months later at a conference in Cincinnati with ‘You and your damned straw-poll!’ I then realized why the editors had meanwhile asked me to withhold the names in my paper, which I happily did.
It was at the later conference that I learned a bon mot of Mark Twain that somehow seems appropriate here: ‘If the end of the world is nigh, it is time to be in Cincinnati. Everything comes to Cincinnati twenty years late.’
The Ultimate Things (p. 15) I mentioned in the Preface the difficulty of writing without using temporal notions. The curious state of modern physics as outlined in Box 2 compounds the problem. Because quantum theories are obtained from classical theories by so-called quantization, and classical concepts are much closer to everyday experience, the language used by most physicists, myself included, often seems to imply that the classical theories are somehow deeper than the quantum theories obtained from them. But that is certainly only a reflection of our way to the truth. What is needed is a clear language in which to describe the quantum truth directly and an explanation, based on it, of why the world appears classical to us. I am proposing the notion of a Now as the basic quantum notion.
Getting to Grips with Elusive Time (p. 17) The idea that instants of time are distinct entities that should not be thought of as joined up in a linear sequence is a powerful intuitive experience for at least one non-scientist. A few days after the Sunday Times published its article ‘Time’s assassin’ about my ideas in October 1998, I received by email a ‘Question for Julian Barbour’ from Gretchen Mills Kubasiak, who had read the article about me. She introduced herself with: I am merely a girl who lives in Chicago, works for a construction company and finds herself thoroughly captivated by your ideas. In fact, I have been unable to think of little else this past week.’ She asked if she could put a question to me. Well, who could resist that request? I said yes, asking if by any chance, with her first name, she had German ancestry, and commented: ‘I guess you know the German expression Gretchenfrage and its origin in Goethe’s Faust, when Gretchen asks Faust about his attitude to religion and if he believed in God. It was especially nice to get your Gretchenfrage.’ Subsequent correspondence persuades me that ‘merely a girl’ might not be the most accurate description of her, since she is a voracious reader and traveller (among much else). Some of her thoughts about time are worth passing on:
Several weeks before I read the London Times article which brought your ideas to my attention, I started having a debate with a friend of mine on traveling. He stated that when a person travels between two places, it is the time spent on the journey which makes the person able to appreciate and comprehend the final destination. Only by making a linear tour of the world and having a passage of time connect the two locations are we able to understand our final destination.
I disagreed. I have always believed that our lives are made up of individual moments that layer and co-exist with other moments, not a linear sequence of events. I did not accept his notion that time spent on a journey is relative to one’s experience at their final destination. The passage of time, that for my friend constituted the journey, did not exist for me. That is not to say that what he viewed as his journey did not consist of moments but I could not accept that they were relative to the moment of the final destination simply because they preceded it.
Despite the fact that I had these beliefs in my head, I found that I lacked the vocabulary to make a satisfactory argument on paper. It is one thing to state your beliefs and quite another to be able to back up your argument. I had developed a few descriptive examples of moments in my life that I believed began to illustrate this idea but I knew of nothing that would support them.
One of my ideas addressed my moments with Buckingham Palace. As a small child I had listened to my mother recite the poem about Christopher Robin’s visit to the changing of the guard and I stood silently alongside him and Alice. As a young girl I watched on television the newly married Prince and Princess of Wales venture forth onto the balcony to greet their public and I stood among the crowds. In both instances I was not ‘there’ and yet I was. When I actually stood in front of the palace as a teenager, the physical journey associated with that moment mattered not. What mattered were these other moments. When I stood in front of the palace, I was living not just that moment but co-existing with the other moments as well.
Then I came across the London Times article outlining your notion of the illusion of time and a spark of recognition within me was lit. Something I had always felt, but had never been able to express, was suddenly being put into words.