Limits to deductive science

Prof. L.M. Brown 

10 November 2013

Let me start by recounting some of the advances in science which have occurred since my birth.  First, recognition of the scale of the universe outside our solar system: our galaxy only one among many thousands of millions in a population of galaxies about twelve thousand million years old, embedded in a space ever expanding but originating from a mysterious cosmic event, the zero of space and time.  Second, release of almost unlimited energy, whether beneficial or harmful, from the atomic nucleus.  I remember very clearly – I was nine years old – the headlines in the Windsor Star in Ontario proclaiming the destruction of Hiroshima by an atom bomb.  Third, the picture of an active earth, about one third the age of the universe, now heated by radioactivity, with its crustal continents floating on a slowly churning mantle: volcanoes and earthquakes seen as shudders in a steady process of division,  and collision.  Fourth, the discovery of the molecular processes underlying human inheritance and evolution, resulting in an increasingly certain picture of the history of homo sapiens.  We – humankind - originated in the Great Lakes region of Africa perhaps three hundred thousand years ago, but with ships and migrations gradually populated and exploited the rest of the world.   Fifth, the development of antibiotics and the increase in human lifespan by at least ten years.  Sixth, the observation of the nanoworld, including viruses and transistors, vital components of the silicon chips which now underlie our civilisation.  Before I was born, no human had observed anything smaller than a wavelength of light; now the direct observation of atoms, ten thousand times smaller than that, is commonplace.  It is a new world.  I am very proud to have taken part in the voyage of discovery.

The novel vistas opened up are very real: the age of the universe is measured in our years, even though our solar system did not exist for most of the time; the magnitude of atoms is measured using the same metric as our height and weight.  Instruments are the key to these advances, so when I say ‘see’ I refer to lenses, spectrometers, electric currents, and so forth: but, although always contingent upon further observation and debate, I see no reason to dispute the reality of the pictures I’ve described.

On the very grand scale, and on the very minute scale, science has opened our eyes, enlarged our world in space and time.  However, we are still unable to predict with any reliability the incidence of specific earthquakes, or the weather a week from now.

In September 2011 seven men, four scientists, two engineers, and a government official, went on trial in Italy, charged with criminal manslaughter for the deaths of some of the three hundred and nine people killed in a big earthquake in the city of  L’Aquila in central Italy.  Although the citizens had detected earth tremors, and were starting to panic, to sleep in the streets and to leave the city, the scientists correctly explained that the chance of a big earthquake was very small, negligible, although specifically whether one would occur in the immediate future is an question they could not answer.  As a result, several citizens remained in their houses and were killed when the earthquake struck.  It seems that the Judge scarcely listened to the case put by the scientists, but blamed them for not communicating the risk properly, and therefore guilty of manslaughter.  There is an excellent account of this important case in the Times Higher Education Supplement of October 2013.

The unpredictability of earthquakes is easily grasped.  In a simple hour-glass egg timer, the individual avalanches in the growing cone of sand at the bottom of the glass cannot be predicted, even with the most powerful computers: there are too many variables.  The trajectory of each grain is indeterminate: one cannot ascertain where each will end up, although you might know where they are located just before turning the hour glass over and starting the avalanche processes.   Yet the sand falls regularly enough so that you can accurately time the boiling of an egg to make it either soft boiled, or hard boiled: the timing is an ‘emergent property’ of the egg timer, yet the detailed fall, bounce, and slide of the grains of sand cannot be foretold.  You can imagine yourself living on a grain of sand.  You know that your life is precarious, and you know where are the danger zones, but you cannot know whether you will survive the next few seconds or not.  Avalanches on ski runs are of course the same, and so is the weather: the famous ‘butterfly effect’ renders a range of predictions impossible.  Of course, bigger computers greatly improve the forecasting, so that recently the hurricane which struck England last week was predicted a few days in advance, although its exact trajectory could not be foretold until a few hours before it struck.  The prediction undoubtedly prevented much damage, and saved many lives: but not those upon whom the trees fell and the floods washed away.

What is the moral of this story?  I think it is to encourage scientists to be humble, not to claim too much, and to respect those who trust other ways of coping with the uncertainties of life.  Surely it is also for others not to expect too much of scientists, but also to recognise the ambition and success of the scientific endeavour.  The enemy which leads to tragedy is self-righteousness: smugness and the reluctance to listen to other points of view.  I believe that the sending to prison of seven conscientious scientists is a tragedy, not only for them, but for the public understanding of science.

If I could adopt an image from the late, great, Joseph Needham, formerly a Trustee of the nascent Robinson College: one imagines a troika drawn by three horses: the first is religion, by which I mean recognition of the spiritual side of life, capable of comprehending our fragility in the face of uncontrollable and irresistable forces; the second is science, capable of widening our horizons to reveal more and more of the world we inhabit, and capable also of improving our material lot; the third is politics, participation in our society, with its law courts and parliaments, and whatever other insitutions there may be.  Religion is for the spirit, science for the body and mind, and politics for hope for the future of our children and grandchildren.

A troika cannot reverse.  It can make wide circles and return along a former route if required, but it cannot travel backwards.

But who or what holds the reins?  Who keeps the team of horses balanced and peaceful?  I would like to think it is charity.  Charity  in its old-fashioned meaning: that ability to empathise with others, to puncture the armour of self-righteousness by human contact, to listen and to try to understand, to forgive.  This is close to what my father used to call ‘Judgement’ – not to be carried away by self-involvement and self-deception, not to proselitise, but still to try to communicate to your fellows what you truly understand.