So, quick question for you. What is life?
Sorry, that’s a trick question, for the answer to this is anything but quick. The mind-boggling complexity that is life, even something as “simple” as a bacterium, somehow arises from atoms and molecules. And yet, physics and chemistry as we currently know it seem incapable of answering how life’s complexity emerges from its constituent parts. With The Demon in the Machine, well-known physicist and cosmologist Paul Davies takes a stab at it, saying we are on the verge of a breakthrough.
Davies is not the first to ask this seemingly simple question. He takes as his starting point the 1944 book What is Life? by the famous physicist Erwin Schrödinger. Schrödinger and others noted that the very existence of life seems to violate one of the fundamental laws of physics: the second law of thermodynamics, i.e. the universal tendency towards disorder, or, more formally, an increase in entropy. But life does the opposite, creating order and complex, organised structures. If life is to spring from basic physics at the atomic level, how does it do that? Before DNA was identified for what it is, Schrödinger already intuited that for life to go against the second law of thermodynamics, there had to be a molecular entity encoding information on how to build an organism.
Both Schrödinger and Davies agree that this reductionist view isn’t the full answer. Davies contends that it is the flow of information that sets living matter apart. To make his point Davies surveys disparate fields of scientific enquiry. I found the resulting tour to be as much frustrating and meandering, as I found it to contain brilliant flashes of insight.
An example of the former is Davies introducing a classic 1850s thought experiment, known as Maxwell’s demon (the demon referred to in this book’s title). Without going into the details, this thought experiment would allow violation of the second law of thermodynamics, but only by making unrealistic assumptions of frictionless devices running without energy input. Somehow, after discussing both information theory and molecular biology, Davies links this to the vast amount of information management that living cells engage in.
“[…] Davies contends that it is the flow of information that sets living matter apart”
Similarly speculative is a chapter on quantum mechanical effects in biology. At the atomic scale, things behave very differently than we experience in our macro-world, leading to all sorts of counterintuitive and weird effects. Quantum effects have been implicated in photosynthesis and bird navigation (see also Life on the Edge: The Coming of Age of Quantum Biology). Most of this chapter, too, went right over my head, and Davies himself ends the chapter on a cautionary note.
Closer to home, and thus easier to understand for me, were the chapters where Davies explores the idea of cells doing computations, with networks of gene regulation forming chemical “circuit boards” that can function like logic gates doing AND or OR operations the way electronic circuit boards can do. Or take the question of how random variation and natural selection can give rise to such exquisite solutions to life’s problems. Davies here mentions Andreas Wagner’s book Arrival of the Fittest: Solving Evolution’s Greatest Puzzle (I read that upon publication and it blew my mind – now that’s a book of great clarity). He introduces the very interesting observation of mutation hotspots: specific genes that, in case of emergency, can mutate much, much faster than average. Related to this, he considers cancer (which is, at heart, unlimited cell proliferation) to be an evolutionarily ancient back-up strategy for a cell to escape stressful conditions.
Davies similarly tries his hand at answering the questions when, where, and how life began. He touches on some interesting though speculative ideas, such as the existence of a shadow biosphere, i.e. a group of lifeforms existing right alongside us resulting from an independent second genesis. He believes that explaining life’s origin will come from studying information-processing systems of sufficiently great complexity. Finally, Davies applies his ideas about information to questions of consciousness, free will, and the human brain.
“My concern is that this […] ends up being a form of vitalism-redux, where we substitute “mystical essence” with “information””
Ultimately, my problem with The Demon in the Machine is two-fold. First, its subtitle teases at some sort of grand synthesis. However, the book delivers a series of mostly speculative and often meandering chapters, some of which, in all honesty, I struggled to comprehend. Or really, I struggled to see how this all comes together – in my opinion, Davies doesn’t really tie up all these strands into a convincing argument. Second, living things used to be thought of as normal matter animated by some extra, mystical essence, a life force or ethereal energy, whether it was thought to be the breath of life, heat, electricity, or a soul. On page 8, Davies asserts that this era of vitalism is dead. My concern is that this “field so new and fast-moving that it lacks a name”, as the dust jacket informs us, ends up being a form of vitalism-redux, where we substitute “mystical essence” with “information”.
Davies is throwing out many interesting questions in The Demon in the Machine, that is for sure. If you like a thought-provoking book that skirts the borders of biology, physics, informatics, and philosophy, this book is just your ticket. Time will tell whether this incipient field will live up to its promises, but for now this book did not convince me to come off the fence just yet.
Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.
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