Lee Smolin

TIME REBORN

From the Crisis of Physics to the Future of the Universe

That idea gave a central role to time, and in the present book Smolin takes this further. The idea that time is unreal, an illusion, is ancient and widespread. Truth, justice, scientific laws, and the divine realm are often said to be outside time. This was Plato's view and it was also held by Einstein. Smolin, in contrast, thinks that time is utterly real. In fact, it is the most real aspect of our perception of the world.

Smolin has authored or co-authored numerous scientific articles about his ideas; here he presents them in non-technical language for non-specialist readers. The book has two parts. The first describes and criticises the predominant view, according to which past and future exist and are fixed, and the second and longer part presents Smolin's alternative opinion. The fixed view of time is often referred to as Einstein's block universe. Einstein himself is said to have found solace in the notion of timelessness: "People like us, who believe in physics, know that the distinction between past, present, and future is only a stubbornly persistent illusion."

Smolin experiences the emotional appeal of this understanding of time, particularly in the way it has been developed by another physicist and friend, Julian Barbour.

Barbour's theory of timeless quantum cosmology offers palpable consolation for our mortality. I can feel it. I wish I could believe it. You experience yourself in a collection of moments. According to Barbour, that's all there is. Those moments always are, eternally. The past is not lost. Past, present, and future are with us, always. Your experience may figure in a finite set of moments, but those moments never go away or cease. So nothing comes to an end when you come to your last day. It's just that now you are experiencing a moment that has all the memories you will ever have. But nothing ceases, because nothing ever started. The fear of death is based on an illusion, which in turn is based on an intellectual mistake. There's no flow of time running out, because there's no flow of time. There are just, and always are, and always will be, the moments of your life.

Scientific laws are not fixed but evolve, Smolin thinks, which leaves room for at least a degree of genuine originality and innovation. The future is not wholly predictable. But what influences how the laws evolve? On this question we encounter a considerable surprise in Chapter 12, where Smolin advances what he calls the Principle of Precedence. This means that the laws form habits, so to speak, depending on what has happened before. Smolin uses the analogy of the Anglo-Saxon Common law, whereby judges act in the way that judges have done in the past when presented with similar cases. Something of the kind might well be operating in nature, he suggests.

When we do an experiment that we have carried out many times before and in which we have always gotten the same result, we can reliably expect that result in the future. … We can expect that the next time we throw a ball it will travel along a parabola, which is what has happened every time we have done this in the past. Usually we say that this is because the motion is determined by a timeless law of nature, which being timeless, will act in the future just as it has acted in the past. So timeless laws preclude genuine novelty.

Although Smolin insists that he is writing about science, not metaphysics, there are definite philosophical implications in what he says, notably in the passage about Julian Barbour quoted above. In an epilogue he finds connections between a prevailing belief that reality is timeless and threats to our survival, including climate change and economic instability. And he concludes with a brief discussion of the problem of consciousness, although the connection of this to the subject of the book seems rather tenuous.

Smolin writes well for the non-specialist reader and the ideas he discusses here are profound and important. How far they can be rendered in words rather than mathematics is difficult to know. There is some repetitiveness in the text and the argument is not always easy to follow, but the central idea—that there are major difficulties with the notion of timelessness that has characterised much of Western thought since Plato—comes across clearly. The relevance of this for theological speculations about the nature of God is only touched on obliquely here and there, but such questions certainly arise if Smolin's rejection of timelessness is right.

5 July 2014