(Steven Poole’s post from the GUARDIAN UK Book Review on 18 Jan 2019.)
The
Demon in the Machine by Paul Davies review – what is life? A new theory, which
centres on information, is providing some answers in this lucid but speculative
exposition.
In
1943 the great physicist Erwin Schrödinger, of both-dead-and-alive-cat fame,
gave a series of lectures at Trinity College Dublin, published the next year as
his book What Is Life? He supposed that genes must take the form of a “huge
molecule” containing a “miniature code” to direct the subsequent development of
the organism.
Francis
Crick and James Watson, inspired by Schrödinger’s work, later proved him right
when they, along with Rosalind Franklin and Maurice Wilkins, discovered the
structure of DNA.
But Schrödinger’s central question remains unanswered. There is still no agreed-on definition of what life is, let alone how it started. Maybe, some suggest, there are biology-specific laws of nature that we have yet to identify. Indeed, Schrödinger himself argued that “living matter, while not eluding the ‘laws of physics’ as established up to date, is likely to involve ‘other laws of physics’ hitherto unknown”.
One
fashionable approach now in biology is to suppose that these laws have
something to do with “information”. In the age of mechanical inventions, it was
thought that animals were like marvellous clockwork machines, and the entire
universe was a sort of fabulous Meccano construction designed by God. Now we
are in the information age, it seems obvious to us that the human brain – even,
in some theorists’ view, the cosmos as a whole – must be a computer, and that
information itself somehow underlies reality.
The
conceptual problem here is that the idea of “information” makes sense only in
the context of an observer for whom something out there, in the indiscriminate
jumble of the world, counts as information. Before life exists, there cannot be
any such thing as information.
It
is to the credit of the physicist Paul Davies, then, that in this brilliantly
vivid little book he is careful to remind the reader that such uses of
“information” should be bracketed with provisos, even as he shows what we can
do with them. It seems irresistible to say, to begin with, that cells “signal”
to one another chemically, or that flocking birds and shoaling fish are
exchanging “information” with their neighbours about speed and direction. But
things get a lot weirder when Davies applies to biology ideas from
thermodynamics and the mathematical theory of information.
The
“demon” of the title is Maxwell’s Demon, named after a thought experiment by
the 19th-century Scottish physicist James Clerk Maxwell. Imagine a box of gas
with a partition containing a tiny door. A supernatural intelligence could open
the door to let fast-moving particles go one way and slow-moving particles the
other. This would eventually result in two different temperatures of gas either
side of the partition, reversing entropy and enabling work to get done free.
The big idea is that nature itself might take advantage of the superefficiency of a demonic approach to information, and understanding the information flow in organisms might be the missing part of our scientific jigsaw puzzle. Davies proceeds to explain the maths of cellular autonoma, the ridiculously fine-tuned machinery of the cell and the workings of the “hive mind” in social insects.
The information flow in genetics, too, is far more complex than once thought, a point piquantly illustrated by some perverted worm-botherers. These researchers discovered that by cutting the head and tail off a worm and applying electricity – which disrupts the information flow in regrowth – you can get a worm with a head at both ends. If you then cut that worm in half, just for lolz, you get two new two-headed worms, even though they have exactly the same DNA as the original one-headed worm.
The
informational approach, in Davies’s elegant and lucid exposition, is extremely
promising, but it remains highly speculative, as he himself laudably emphasises
while offering his own final thoughts on consciousness (as “integrated
information”), and the possibility that “laws of nature” themselves evolve
through time. Perhaps, he adds, these laws might, in some way not yet
understood, be inherently “bio-friendly”.
This is a maverick idea, but not a new one. The philosopher Thomas Nagel was widely ridiculed by scientists a few years ago when, in his book Mind and Cosmos, he suggested that there might be “teleological” laws ensuring that consciousness would arise in the universe.
Teleology
– the ancient idea that things strive towards a purpose – is not now
respectable, and Davies himself refers to it as a “problem” to be avoided. And
yet right at the end of this book, he suggests that “the emergence of life, and
perhaps mind, are etched into the underlying lawfulness of nature”. That idea
is nothing if not teleological – which is no good reason, by itself, to think
it untrue.
