Thursday 4 February 2010

Organising chaos: a natural imperative

The secret life of chaos, BBC 4, presented by Professor Jim Al Khalili

The secret life of chaos is the first in the World of wonder series which runs throughout 2010 across the BBC, and raises the exciting possibility of answering the question of how life first began. Presented effortlessly by Professor Jim Al Khalili, a relative newcomer to our television screens, the tone is comprehensible without being patronising. Professor Khaliili communicates a quiet passion quite unlike the infantile exuberance of other science presenters, who either shout excitedly or whisper in theatrical asides.

Indeed, it can seem easy to shrug off the question of life’s beginning with casual reference to the big bang. Yet this leaves the mystery of how non-living matter came together to make the soupy sludge where DNA molecules first replicated themselves to form the genetic codes that defines all living things, still quite unexplained. So,it’s fascinating when Professor Khalili unravels how a few chemical compounds like water, chalk, coal and air with a few traces of iron, phosphorous and sulphur became complex organisms with differentiated cells creating the skin, the eye or the limbs of animals and humans.

Khalili begins with the brilliant mathematician, Alan Turing, most famous for his wartime work in Station X at Bletchley Park where he broke the German navy’s Enigma code and helped the allies win the war. But Turing cracked more than a communication code.

Attempting to intellectualise his feelings following the death of his lover and partner, Christopher Morcom, Turing began investigating what happens to the mind after death, using mathematics to describe biological systems and subsequently intelligence. This was a novel application of mathematics and led to his breakthrough work on morphogenesis, which describes how the identical cells in an embryo begin to clump together and then differentiate - without thought or central co-ordination – to form the skin cells, the eye cells and so on. Before Turing, no one had understood how this self-organization worked. In his first paper, The Chemical Basis of Morphogenesis, he described self-organization, the process by which simple equations acting on simple molecules move towards greater complexity.

Professor Khalili illustrates this idea by asking us to picture a steady wind across the desert sands and imagine how the millions of grains of sand become ripples and then waves and then dunes, each grain having no knowledge of how it became part of a more complex structure. Chemicals act in the same way: featureless chemical soup coagulates into blobs and patches not dissimilar to the markings on animal skins.

Turing had shown how a simple mathematical process could result in formations of great complexity without involving any conscious thought. Once the pattern is there, evolutionary selection, as described by Darwin, decides whether the pattern is passed on.

To the detriment of science, Turing’s work was cut short by his tragic suicide after being prosecuted for sexual indecency and forced to take female hormones to ‘cure’ his homosexuality.

Al Khalili moves on to Boris Belousov in Russia, who discovered the law of thermodynamics could be reversed when he noticed that a liquid mixture of chemicals oscillated between clear and coloured states as though some hidden metronome were at work - a real world example of Turing’s ideas. In another tragic confrontation over conventional views and scientific innovation, the Russian scientific establishment rejected his paper and in despair, he gave up science altogether.

Other scientists were to show that a mixture of chemicals left in Petri dishes would form beautiful and ever-changing patterns out of nowhere; pulsing like our heart cells and once again reproducing Turing’s equations.

Al Khalili informs us that mainstream science was hostile to these discoveries as they ran counter to the orderly mechanisms of Newtonian physics, which can predict how a process will unfold. For instance, the law of gravity accurately predicts how the planets move around the sun and got men to the moon. When this model did sometimes behave unpredictably, it was considered the work of malign, outside influences. This runs counter to the idea of self-organization, which requires no outside influence.

At the same time as the moon landings, a group of ardent Newtonians found ‘a devil in the detail’ which they called chaos. In science, Al Khalili tells us, chaos has a specific meaning. It means a system described by a mathematical equation that can be unpredictable without the interference of any outside influence.

Meanwhile, in the USA Edward Lorenz was working on mathematical equations to predict the weather, but his simple equations for air currents made no useful predictions whatsoever. He discovered that the tiniest difference in the way something is configured, for instance the starting position of the cogs in an orrery, leads to bigger and bigger variations. This gave rise to the familiar question:

‘Does the flap of a butterfly’s wing in Mexico cause a tornado in Texas?’

Down under in Australia, Robert May was studying how animals change over time and noticed that immeasurably small changes in the way they reproduced caused great fluctuations in population.

It seemed the end of the Newtonian dream. We could never know the starting point accurately. Scientific certainty dissolved. Chaos was seen everywhere, hard-wired into every aspect of the world in which we live. The global climate could change, the stock market could crash and there seemed to be nothing we could do about it. ‘This is true’ says Al Khalili, ‘but we shouldn’t be scared. It’s a basic law of physics. It allows for the natural world to be unpredictable but it can also allow it to create pattern and structure – order and chaos can occur simultaneously.’

That the natural world can behave in complicated ways based on simple mathematical rules is a property known as coupling or feedback, creating a loop, whereby small changes become rapidly amplified and where one can describe each process mathematically but can’t predict the outcome – the butterfly effect with a slight tweak – the creation of beautiful patterns. The same process creates both chaotic behaviour and patterns. Pattern formation is a basic part of the universe.

Benoit Mandelbrot came up with a new understanding again. Working on finding the mathematical descriptions of irregular shapes found in nature like branching trees, fluffy clouds or mountain ranges, he noticed a common feature; that of self-similarity, when the same shape is repeated over and over again ad infinitum at smaller and smaller scales. He called these fractals. He came up with a simple equation to draw a remarkable shape that describes this process. It came to be known as the Mandelbrot Set or the thumbprint of God. The equation Z↔Zⁿ+C feeds back on itself so that each output becomes the starting point for the next equation producing complexity infinitely.

This was the first time I had even heard of the Mandelbrot Set and seen it produced in 3D. It was quite astonishing. It really seems to describe the universe as we see it. Looking up at the sky, the Mandelbrot Set seems to describe the way we imagine the stars and other galaxies like our own, dying and being reborn, constantly repeating with slight differences and at ever-smaller scales and greater complexity.

Al Khalili draws our attention to the way flocks of birds behave. Each bird obeys simple rules but the flock does amazing and unpredictable things and never repeats the shapes it produces; like the Belousov patterns, each shape is slightly different.

According to Al Khalili chaos theory appears to explain why life exists, how dust becomes human beings.

‘Evolution’ he explained ‘was a process that used raw materials provided by nature, its inherent self-organizing capacity, experimented, kept what worked in an unconscious way - mindless yet creative – and over a cosmic timescale of three and half billion years the first life forms appear.’

A computer can mimic this evolutionary process in a shorter time period. We are shown scientists who have created virtual brains that can control virtual bodies. The brain is programmed to be completely random and is shown to select the best feature over a period of time so that what was an initial blob with limbs that kept falling over ends up as a stable figure walking upright.

The simple rule, that an organism must replicate with a few simple mutations allows for selection, then feedback and the recreation of the next organism.

This design does not require an interfering designer. It is inherent in the universe.

This all made sense to me as a non-expert and wasn’t patronising. I will certainly be tuning in on Thursday for the next programme in the series, Chemicals – a volatile history.

See a clip from this episode here:

BBC 4, Thursday, 9pm


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