Decoding Reality: The Universe as Quantum Information
By Vlatko Vedral
Oxford University Press £16.99, 240 pages
FT Bookshop price: £13.59
Since the start of the 20th century, theoretical physics has provided a rich seam for authors keen to explain in popular terms the nature of “reality”. We already know, courtesy of Albert Einstein, Niels Bohr and others, that reality is, to quote JBS Haldane, “queerer than we imagine and queerer than we can imagine”.
The reality we can imagine involves elementary particles – protons, neutrons and electrons and even more elementary particles such as quarks and neutrinos. These are reassuringly physical, even if they exhibit the disturbing quantum properties of being in two places at once and able to communicate over astronomical distances.
Now Vlatko Vedral, professor of quantum information science at Oxford University, seeks to persuade us that at its most fundamental, reality is encoded in information. This alone, he argues, is enough to explain quantum mechanics as well as biological inheritance, sociology and the stock market. (Interestingly, Claude Shannon, the “father” of information theory, made a fortune out of shares but died with his investment secrets intact.)
“The reader may not agree with my ultimate view of encoding reality,” Vedral writes, “but hopefully he or she will find the discussion of the separate pillars (biology, economics, gambling and so on) valuable in themselves.” Certainly he provides conclusive evidence that gambling on the lottery is a waste of money.
An immediate question, however, is how to define “information”. Most of us have a rough idea. Vedral has a very precise, scientific definition: it is the logarithm of the inverse of the probability of an event. Or, more simply, the more unexpected an event, the more information it contains.
On this somewhat counterintuitive foundation, he builds castles of mathematical logic: “In biology, for example, an event could be a genetic modification stimulated by the environment. In economics, an event could be a fall in a share price. In quantum physics, it could be the emission of light by a laser when it is switched on. No matter what the event is, you can apply information theory to it. That is why I will be able to argue that information underlies every process we see in nature,” he says.
Vedral writes in an amiable, unaffected style but this is a difficult book for the non-specialist. He has the slightly irritating habit of starting to explain a key point, then wandering off into an anecdote, in the manner of a lecturer diverted by a passing thought. The sense that one is reading an introductory text to a university course is reinforced by a series of “take-home” lessons at the end of each chapter.
Unusually, perhaps, for a work of this kind, the author devotes space to religious views of the existence of God. I particularly like the Cappadocian idea that we cannot say that God exists because existence is a human notion and as such may not apply to God. Vedral thinks this view reminiscent of the laws of physics. Queerer, indeed, than anything we can imagine.
Alan Cane is an FT technology writer