The Demon in the Machine by Paul Davies

Publisher:        Allen Lane (an imprint of Penguin Books)

Published:       2019

ISBN-13:        9780241309599 (2019 hardback edition)

ISBN-13:         9780241360934 (2019 trade paperback edition)

Pages:             236

Words:            80,000 approx.

The subtitle of this book is: How hidden webs of information are solving the mystery of life.  A less succinct description might be that this is a book, amenable to the scientifically informed reader, which describes a range of new and exciting discoveries and ideas in the general area of the physics underlying life at the molecular level and of just how life processes and uses information at the molecular level.

Prof. Davies has had a long and distinguished career, both academically and as an author and lecturer with the aim of making science accessible to a popular audience.  In addition to his purely scientific work, Prof. Davies has a long-standing interest in interactions between science, religion and spirituality, and his work in that area has been recognised by the Templeton Prize.

The book packs in a great many ideas and accounts of a great many recent discoveries and ideas.  It begins with the question What is Life? and the ideas suggested by Schrodinger in his 1943 lectures with that title. Davies points out that while it is possible to produce a list of properties possessed by some (and in some cases all) life forms, it has not thus far been possible to give a single definition which clearly distinguishes a living organism from non-living matter.  He points us, in particular, to Schrodinger’s point that living things appear (but only appear) to defy the second law of thermodynamics by achieving local reductions of entropy.  A brief digression on vitalism follows, in which the traditional forms of that idea are rejected.

Next, Davies moves on to the relationship between energy, entropy and information – with a particular emphasis on information as it is stored, processed and used by living cells at the molecular level.  He reminds us of Maxwell’s demon – a mythical creature invented by Maxwell as part of a thought experiment in which the second law of thermodynamics also appears to be ignored.  The resulting discussion brings in current ideas of fundamental physical relationships between entropy, information and energy.  The idea of an ‘information engine’ is also introduced, and it is claimed that such devices have been built and demonstrated at the nanomachine-scale.  The idea of a very small and useful demon is generalised somewhat.  It is suggested that many of the chemical (or physical) mechanisms at work in DNA copying and error-correction, and in the transcription of genes into protein molecules, can be regarded as using real-life demons – but without the un-physical attributes that Maxwell’s demon would have had if it had been real.

Later, the discussion turns to evolution and to some apparent violations of the long-held doctrine that the flow of information between genome and proteins is one-way – from the former to the latter.  Davies cites several studies which appear to show information flowing in the opposite direction – allowing a sort of Lamarckism.  As part of the same account of evolution, evidence of a phenomenon called ‘adaptive mutation’ is described.  This appears to be a process by which some organisms can enhance their own processes of evolution in challenging circumstances.  The existence of epigenetic effects is also referred to as part of this discussion, and some very puzzling experiments on some unfortunate worms which have been cut in half by researchers are described.  The term ‘Darwinism 2.0’ is used in the book to refer to the new understanding these reported discoveries appear to lead to.

The new field of quantum biology is then briefly visited.  Prof. Davies makes the important clarifying point that chemistry relies in fundamental and unavoidable ways on quantum processes, and therefore there in no question but that quantum processes are involved in biology and in most other things.  He refers to those well-accepted effects as trivial quantum processes and to other effects whose role in biology is more contentious as non-trivial quantum processes.  In the latter category we have such things as electron tunnelling and quantum entanglement – both thought by some to have some role in fundamental biological processes. 

Ideas for quantum computing are discussed – together with the huge consequences likely if any of those ideas become practical reality.  Davies points out that quantum computing systems could perhaps have appeared naturally and might be very valuable as information processing systems within living things.  He suggests, as a personal conjecture, that nature is unlikely to have overlooked that opportunity.

Next, the origin of life is addressed.  Prof. Davies makes the point that there is absolutely no evidence that life has appeared anywhere else in the universe and therefore (the allegedly huge number of habitable planets notwithstanding) it could be an exceedingly rare occurrence.  He then summarises current ideas and understanding of just how the simplest living systems could have formed.  That summary concludes that no convincing mechanism by which a system capable of replication with imperfect inheritance (and therefore capable of evolution) has yet been proposed.

This book is a compelling and up to date read packed with facts and ideas sure to set any thoughtful person thinking.  The emphasis throughout on information processing as a fundamental facet of life seems completely reasonable.  There is a suggestion, at several points, that new physical laws will be needed to understand how physical systems become physical systems which are also alive.