Read this book for a really entertaining account of the way life operates at the level of a cell to process information from a bestiary of truly fascinating creatures that make life what it is. If there is a more comprehensive account of the cell in equally accessible language then I want that on my reading list. I also learned a number of unexpected new things about the evolutionary process which I found helpful and will use in future discussions. For the question “what is life?” however, never mind the further question “what is consciousness?” I am not sure that it is much help.
I’m not a biologist, I’m a physicist and cosmologist, so my approach to tackling big questions is to dodge most of the technicalities and home in on the basic principles. And that’s what I do in this book. I’ve tried to focus on the puzzles and concepts that really matter in an attempt to answer the burning question: what is life? [p1]
Well, I disagree. There are many concepts that matter in any discussion about either the nature of life or the nature of consciousness and I do not agree that Davies has reviewed them, or even the most important of them. Rather late in the book he does notice a context in the history of ideas and especially the early Enlightenment:
Physics as we know it developed in seventeenth century Europe, which was in thrall to Catholic Church doctrine. Although Galileo, Newton and their contemporaries were influenced by Greek thought, their notion of physical laws owed much to monotheism, according to which an omnipotent deity ordered the universe in a rational and intelligible manner... [p210]
The Newtonian concept of a mathematical universe bound by fixed laws seems appealing to Davies, when he writes:
..if the emergence of life, and perhaps mind, are etched into the underlying lawfulness of nature, it would bestow upon our existence as living, thinking beings a type of cosmic level meaning. [p257]
Either consciousness violates quantum mechanics or it is explained by it. [p207]
But at the same time, he points to the ideas of Godel and of Turing to suggest that our universe may not be lawful in the way envisaged:
Physicists have traditionally clung to a very restrictive notion of laws, dating from the time of Newton. ... Since it was held that the law of the universe reflect the divine nature, it followed that the laws must also be unchanging. ... This idea has been around so long we scarcely notice what a huge assumption it is. But there is no logical requirement it must be so, ...Indeed, I have already discussed one well known example from fundamental physics in which the laws do change according to circumstances: the act of measurement in quantum mechanics... [p210]
Gödel’s theorem tells us that the world of mathematics embeds inexhaustible novelty; even an unbounded intellect, a god, can never know everything. It is the ultimate statement of open-endedness. [p70]
Given that undecidability is enshrined in the very foundations of mathematics, it will also be a fundamental property of a universe based on mathematical laws. Undecidability guarantees that the mathematical universe will always be unbounded in its creative potential. One of the hallmarks of life is its limitless exuberance: its open ended variety and complexity. [p72]
Newton belongs to that Enlightenment tradition that Jonathan Israel calls the Moderate Enlightenment, which takes up the insights of modern science starting with Galileo and especially Descartes, without allowing them to call into question Christian beliefs or traditional authority. This book’s title is itself an obvious appeal to Cartesian dualism. It is a pity he does not also refer us to the more rationalist tradition which Israel calls the Radical Enlightenment, for which Spinoza is the figurehead, and the alternative concept of monism, which rejects Cartesian dualism and insists that there is only a material natural world, within which are organisms including humans with a capacity for thought, self reflection and reasoning. The dangerous point about Spinoza was that he pursued his line of reasoning without fear of the conclusions, even while calling traditional beliefs into question.
Of course Spinoza did not anticipate Quantum Mechanics, Godel’s incompleteness Theorem or Turing’s concept of undecidability. He did favour the idea of determinism, as an unavoidable consequence of relying on the laws of nature. Then again, his monism entailed a concept of the mind as a product of the sensory system which in turn could be explained as an entirely material, physical apparatus. For Spinoza and other Radicals, the senses which enable us to notice and respond to our environment also enable us to notice and reflect upon ourselves, so that in effect the mind is the self awareness of the body, the body’s nervous system activated by itself, not the activity of a separate, intangible soul or spirit. These ideas are taken up and put to excellent use by Damasio, a neuroscientist, among others and would seem eminently useful for Davies’ topic.
Davies does offer some additional insights for this monistic model of reality, not least in his excellent account of the problems of reductionism. If we wish to account for the phenomenon of life, and beyond that for the mind, in terms of purely physical, material processes, then we will encounter serious limits to what is possible. He describes the stimulus-response process in the nervous system reacting to some event, and notes that in passing signals along one or more nerves, there is a continual transfer of sodium and potassium ions between the axon and its environment, where those ions move about chaotically and are not part of the nervous system itself until plucked out of the chaos or thrown into it. That chaotic environment, in turn, must be accounted for, but this entails a huge elaboration from an ostensibly simple process and becomes open ended, always demanding more information to complete the story until perhaps we account for the universe in its entirety, which is just not a solution.
A hardnosed reductionist may point out that in principle a complete description of the stimulus-response story will nevertheless be present at the atomic level of the system...Even in principle the cause-effect chain we are trying to explain simply does not exist at that level [p204]
In a case such as this, it would seem that reductionism may not only yield an inferior explanation but may in practise be impossible.
This idea of a hierarchy of levels of analysis is not difficult or unusual. He refers to, without explaining it, the notion of emergent properties, which are properties that may be evident at a higher level but are not relevant to a lower one. He also argues that we may operate at more than one level, something that I am less sure about:
The way the laws of physics are currently conceived leads to a stratification of physical systems with the laws of physics at the bottom conceptual level and emergent laws attached above them. There is no coupling between levels. When it comes to living systems this stratification is a poor fit because, in biology, there often is coupling between levels, between processes on many scales of size and complexity: causation can be both bottom up (from genes to organisms) and top down (from organisms to genes). [p216]
I am not sure that the argument is accurate. We can talk about genes at different levels, sometimes as chemical properties, sometimes as information storage and transfer. I don’t know why that is “coupling between levels” rather than switching levels for different purposes.
In short, I found Davies confusing on this topic, which is a pity, because what he seems to be arguing for is the sensible idea that many aspects of biology which are hard to understand and explain in the language of physics and chemistry, may be readily understood in the language of information theory. This does not mean that life or consciousness are explicable entirely in those terms but rather that it is an important aspect of what is taking place.
In the end the book is a collection of entertaining and sometimes important descriptions and concepts worth reading for their own sake but I do not think it succeeds in its stated objective of showing how "webs of information are solving the mysteries of life". Some mysteries, yes, but that is a more modest claim.