This is how it usually goes. I arrive at a party, get myself a beer and start chatting to people. Soon, it becomes apparent that I am a physicist. Various responses follow. Some people never talk to me again. Some politely say that they failed to appreciate physics in school because of the lack of a good teacher. And then there are some who simply exclaim “You must be brainy!”. But, eventually, I am almost always asked “Do you believe in God?”.

The God question is awkward for non-religious physicists like me. If I do not feel like continuing with a philosophical debate (or if I detect that I would be offending religious sensibilities), I usually just reply with a plain “no” and go and get myself another beer. But if I feel that the person inquiring is up for a challenging discussion, I ask them to define “God” in the first place. This request may sound pedantic, I explain, but the whole point of science is to make well-defined conjectures, so that conclusive tests could be performed that would (at least in principle) falsify these conjectures.

Despite attending many parties, I have still not heard a definition of God that is good enough to make me subscribe to it. Yes, we physicists frequently use the word God in our popular writings, but it is usually meant as a synonym for “the universe”, “reality” and “nature”. Science is all about understanding the world we live in, and sometimes this quest is metaphorically called “knowing the mind of God” – in Einstein’s rather poetic words.

A new book sets out to change all this by, among other things, providing an unusually physical definition of God. Information and the Nature of Reality: From Physics to Metaphysics is a collection of non-technical articles compiled by Paul Davies (a physicist) and Niels Henrik Gregersen (a theologian), and written by biologists, historians and philosophers, as well as physicists and theologians. Each article explores the hypothesis that information is at the root of everything. And I mean everything – from atoms to, perhaps, a deity.

The collection starts with historical essays by philosopher of science Ernan McMullin and philosopher-theologian Philip Clayton, who write about materialism (the worldview that states that the only thing that really exists is matter and that all other phenomena are just interactions between different pieces of matter) and its receding hold on philosophy. The stage being set, Davies and fellow physicist Seth Lloyd then present a physics perspective on information. Davies is without a doubt one of the best popular-science writers in the world, and his article demonstrates why. In it, he explains why, in light of modern physics discoveries, materialism is not the most viable philosophy. Lloyd then expands on this idea by introducing the notion that the universe is a giant information-processing device. This is a view that has emerged from my own field of research – quantum computation – and Lloyd is one of its most prominent advocates.

Next, we get a biological perspective, introduced by one of the finest UK evolutionary biologists, the late John Maynard Smith. Smith’s essay elaborates on the central dogma of biology, namely that information flows from genes to the phenotype but never backwards. In other words, the fact that your father was a bodybuilder when you were conceived does not mean you will have a nice six-pack when you grow up. Continuing through the book, however, we soon encounter a somewhat contrary view from anthropologist Terrence Deacon. He argues that Shannon’s theory of information – which states that the amount of information in an event is proportional to how surprising that event is – may not be sufficient to fully capture biological information. What Shannon’s definition lacks, Deacon says, is “semantics”. In other words, the information itself does not make much sense without the medium that interprets this information and gives it a meaning. The debate on meaning, expanded on by Bernd-Olaf Küppers and Jesper Hoffmeyer, naturally leads us into the realms of philosophy, metaphysics and, yes, theology.

The idea that information is the basic building block of reality very much resonates with me. I recently wrote a book, Decoding Reality (see review from August 2010), in which I explained why information is central to biology, economics and sociology, as well as quantum physics, computing and philosophy. At the end of the book, I muse on how information processing might give rise to reality itself. But the last section of Davies and Gregersen’s collection goes well beyond my own speculations. This is the part of the book that I enjoyed the most, even (or especially) when I disagreed with what was being argued.

This section starts with an article by the late Arthur Peacocke, to whom the book is dedicated. As both an ordained priest and a biochemist, Peacocke embodied two very different aspects of information explored in the present book. His essay is on the problem of evil, namely why an omnipotent and benevolent God would allow evil to exist in the world. Peacocke maintains that evil is simply necessary, since for any creation of good to occur, something first needs to be destroyed (he views the extinction of species in the process of natural selection in this way). So far, so good. Then the Roman Catholic theologian John Haught makes a curious suggestion: an event that has the maximum amount of information – in other words, the least likely one – ought to be taken to represent a religious revelation. The pinnacle of this “theological” section, however, is the proposal by Keith Ward that deity is a form of information-theoretic principle. Ward’s proposal is related to the observation that the universe walks a fine line between total disorder and compete order. Logically, it would seem that disorder is a more natural state of affairs if things were left to themselves, and so to get some order out we clearly need an extra guiding principle. And this extra principle, Ward suggests, is synonymous with God – albeit a very different sort of God than an all-powerful creator. Now, there is a definition of God with which I might almost agree!

The problem, of course, is that once we leave the scientific domain, it becomes rather easy to make unfounded speculations about the connections between information and various other religious concepts. For instance, in the last chapter of this book we encounter suggestions that the Christian Gospel of John could be interpreted in information-theoretic terms. Similar parallels are drawn in the essay by Michael Welker, who discusses the information content in the resurrection of the Christ. Carelessly extrapolated, this sort of exposition might lead to arguments similar to Frank Tipler’s nonsensical “proofs” of various Christian dogmas in his two books The Physics of Immortality and The Physics of Christianity. Amusing as such parallels might be, it is doubtful that they will ever lead to any greater enlightenment as to the nature of reality itself.

When the famous British geneticist J B S Haldane was asked if his research taught him anything about God, he replied “The Creator, if He exists, has an inordinate fondness for beetles”. The collection by Davies and Gregersen suggests, in line with my own views, that we could go deeper than Haldane: the ultimate answer might just turn out to be a Creator with an inordinate fondness for bits. Certainly, bits of information are present everywhere we look, and if you want to know more about this novel take on reality, then I highly recommend Davies and Gregersen’s erudite and entertaining collection.