Skip to main content

The Demon in the Machine - Paul Davies *****

Physicists have a habit of dabbling in biology and, perhaps surprisingly, biologists tend to be quite tolerant of it. (I find it hard to believe the reverse would be true if biologists tried to do physics.) Perhaps one reason for that tolerance is Schrödinger’s lecture series and book What is Life?, which had a huge impact on molecular biology and with a reference to which, not surprisingly, Paul Davies begins his fascinating book. 

At the heart of the The Demon in the Machine (we'll come back to that demon in a moment) is the relationship between life and information. In essence, Davies points out that if we try to reduce life to its simple physical components it is like trying to work with a computer that has no software. The equivalent of software here is information, not just in the best publicised aspect of the information stored in the DNA, but on a far broader scale, operating in networks across the organism.

This information and its processing gives life its emergent complexity, which is why, Davies suggests, Dawkins-style reductionism to the gene level entirely misses the point. What's more, the biological setup provides a particularly sophisticated relationship between information and the physical aspects of the organism because the information can modify itself - it's as if a computer program could redesign itself as it went along.

The subtitle 'how hidden webs of information are solving the mystery of life' probably over-promises. As Davies makes clear, we still have no idea how life came into being in the first place. However, by bringing in this physical/information aspect we at least can get a better grip on the workings of the molecular machines inside organisms and how biology can do so much with so little. Here's where the demon in the title comes in. This is Maxwell's demon, the hypothetical miniature being dreamed up by the great nineteenth century Scottish physicist.

Maxwell's demon has the remarkable ability to tweak the second law of thermodynamics allowing, for example, heat to flow from a colder to a hotter body or, to put it another way, providing a mechanism for entropy (the measure of disorder in a system) to spontaneously decrease. Entropy has a strong (negative) relationship with information and Davies shows how miniature biological systems act in a demon-like fashion to effectively manage information.

There's lots to like here, from the best explanation I've seen of the relationship of information and entropy to fascinating coverage of how far we’ve gone beyond the selfish gene. This is not just about basic epigenetic processes (operating outside of genes, switching them on and off and so on) but how, for example, the electric field of a (biological) cell apparently has a role to play in ‘sculpting‘ the physical structure of an organism.

My only real complaint is that in part of the chapter Enter the Demon dealing with information engines and most of the chapter The Logic of Life, describing the relationship between living organisms and computation, Davies fails to put across clearly just what is going on. I read it, but didn't feel I gained as much information (ironically) as I needed from it. There was also one very odd statistic. We're told the information in a strand of DNA contains 'about 2 billion bits - more than the information contained in all the books in the Library of Congress.' There are about 32 million books in the Library of Congress, so that gives us on average 62.5 bits per book. Unless those are very short books, some information has gone astray.

Really interesting, then, from a transformed understanding of the importance of information in living organisms through to Davies' speculation on whether biological systems need new physical laws to describe them. But expect to come away feeling you need to read it again to be sure what it said.
Hardback 

Kindle 
Using these links earns us commission at no cost to you
Review by Brian Clegg

Comments

  1. Nick lane argues in his book The Vital Question that biological systems are not really working to decrease entropy they exist because they essentially dont violate the second law of thermodynamics . I wonder how that reconciles with the theory here

    ReplyDelete
  2. I find it difficult to follow some of this stuff. Not the fluffy conceptual models, but the simple aspergers stuff.

    eg p95, text describing Fig 11, says 'barred lines [indicate inhibition]'. Then seems to use a different term - 'loopy broken arrows' to denote self inhibition. Change of term is confusing but not fatal.

    But Fig 11 contains no broken or barred loopy arrows, only solid ones, thus indicating self activation, not self inhibition. Again, I guess, not fatal, if the reader is expected to be alert for errors or misprints.

    But table 2, P96 shows that in at least 2 cases, the loop is self suppression, so the loop should be broken or barred. Still not quite fatal.

    But then, following Table 2 and Fig 11 together, node G suddenly gets activated in step 8, although in Fig 11 there is no 'incoming [activation] arrow' pointing at it, except for it's own self activation loop, which can never be initiated.

    So what's going on? AFAIK just errors, which I'd hope not to have been included in this book.

    So, how do we read this book? Perhaps best just to gloss over all the clever diagrams & tables, say 'Gee, Whizz, that's all amazing!'

    OTOH if I'm really not understanding a perfectly valid exposition, I'd love to know.

    ReplyDelete

Post a Comment

Popular posts from this blog

The God Game (SF) - Danny Tobey *****

Wow. I'm not sure I've ever read a book that was quite such an adrenaline rush - certainly it has been a long time since I've read a science fiction title which has kept me wanting to get back to it and read more so fiercely. 

In some ways, what we have here is a cyber-SF equivalent of Stephen King's It. A bunch of misfit American high school students face a remarkably powerful evil adversary - though in this case, at the beginning, their foe appears to be able to transform their worlds for the better.

Rather than a supernatural evil, the students take on a rogue AI computer game that thinks it is a god - and has the powers to back its belief. Playing the game is a mix of a virtual reality adventure like Pokemon Go and a real world treasure hunt. Players can get rewards for carrying out tasks - delivering a parcel, for example, which can be used to buy favours, abilities in the game and real objects. But once you are in the game, it doesn't want to let you go and is …

Uncertainty - Kostas Kampourakis and Kevin McCain ***

This is intended as a follow-on to Stuart Firestein's two books, the excellent Ignorance and its sequel, Failure, which cut through some of the myths about the nature of science and how it's not so much about facts as about what we don't know and how we search for explanations. The authors of Uncertainty do pretty much what they set out to do in explaining the significance of uncertainty and why it can make it difficult to present scientific findings to the public, who expect black-and-white facts, not grey probabilities, which can seem to some like dithering.

However, I didn't get on awfully well with the book. A minor issue was the size - it was just too physically small to hold comfortably, which was irritating. More significantly, it felt like a magazine article that was inflated to make a book. There really was only one essential point made over and over again, with a handful of repeated examples. I want something more from a book - more context and depth - that …

Where are the chemistry popular science books?

by Brian Clegg
There has never been more emphasis on the importance of public engagement. We need both to encourage a deeper interest in science and to counter anti-scientific views that seem to go hand-in-hand with some types of politics. Getting the public interested in science both helps recruit new scientists of the future and spreads an understanding of why an area of scientific research deserves funding. Yet it is possible that chemistry lags behind the other sciences in outreach. As a science writer, and editor of this website, I believe that chemistry is under-represented in popular science. I'd like to establish if this is the case, if so why it is happening - and what can be done to change things. 


An easy straw poll is provided by the topic tags on the site. At the time of writing, there are 22 books under 'chemistry' as opposed to 97 maths, 126 biology and 182 physics. The distribution is inevitably influenced by editorial bias - but as the editor, I can confirm …