The Demon in the Machine, by Paul Davies

by
09 August 2019

Denis Alexander looks at new findings inspired by 19th-century theory

THIS does not seem an obvious title for Church Times readers; so some explanation is necessary. The author, a physicist and popular science writer, is drawing upon a “thought experiment” introduced by the famous 19th-century physicist James Clerk Maxwell, now known as the story of “Maxwell’s Demon”.

Maxwell was intrigued to know whether energy could be obtained “for nothing”, and so conjured up a tiny agent — a “finite being” that would quickly open and shut the door in a barrier full of little holes separating the two halves of a box full of gas. The agent would let the faster molecules through in one direction and then shut the holes very quickly to keep them on one side, and do the same in reverse for the slower molecules. Since the faster molecules are warmer, and the slower cooler, one half of the box would become hotter than the other. The heat differential energy could then be used to do work.

Surprising as it might seem, that thought experiment has stimulated much research since, most recently in information theory. The Demon in the Machine is how these “hidden webs of information are solving the mystery of life” because, the author argues, analogous processes to those envisaged by Maxwell are going on in our bodies all the time. In fact, Maxwell was a committed Christian with a Church of Scotland background and never actually used the word “demon” when describing his thought experiment. It was another great Christian physicist, Lord Kelvin, a Scottish Episcopalian, who started calling Maxwell’s imaginary agent a “demon”.

The author of The Demon in the Machine is also inspired by Erwin Schrödinger’s famous book What is Life? (CUP, 1944) to ask precisely the same question in the light of the latest information theory. Life = Matter + Information. This leads on to some fascinating descriptions of the various ways in which actual “demons” have been built as machines. In 2010, Japanese scientists showed how they could turn information into energy with 28-per-cent efficiency, and the author shows how operationally comparable machines have been operating in living cells for millions of years. “Biological information is the software of life.” The book is full of wonderful aphorisms and metaphors, and the author has a great gift for translating complex scientific ideas into memorable pictures more comprehensible for the general reader.

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Davies then goes on to explain how new understandings of evolution are emerging based on epigenetic information, followed by a discussion of the possible roles of quantum events in living cells, and a survey of current thinking on the origin of life. Some brain science and reflections on free will are thrown in for good measure. The pace is breathless, and new ideas pop up thick and fast, becoming ever more speculative towards the end, though the author is generally careful to distinguish established science from speculative ideas that yet require evidence.

This is a book about science, not theology per se, though the author does warn against the bad habit of invoking a “god-of-the-gaps” to “explain” how life begins. But those who hold to a robust Christian theism, with its insistence that through the Word “nothing was made that has been made” (John 1.3), will surely be inspired and encouraged by the world of living information which this book opens up for us. Thoroughly recommended.

Dr Denis Alexander is Emeritus Director of The Faraday Institute for Science and Religion, Cambridge.

The Demon in the Machine: How hidden webs of information are solving the mystery of life
Paul Davies
Allen Lane £20
(978-0-241-30959-9)
Church Times Bookshop £18

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