The Probability of God

We owe a great debt to the British Humanist Association for their advertising campaign on buses: ‘There’s probably no God.’ It’s thought-provoking in a helpful way, because it invites us to reflect not only on God but also on probability.

One of the most unexpected discoveries of modern science is the sheer improbability of the universe. It is shaped by six fundamental forces which, had they varied by a millionth or trillionth degree, the universe would have expanded or imploded in such a way as to preclude the formation of stars and planets. Unless we assume the existence of a million or trillion other universes (itself rather a large leap of faith), the fact that there is a universe at all is massively improbable.

So is the existence of life. Among the hundred billion galaxies each with a hundred billion stars, only one planet thus far known to us, earth, seems finely tuned for the emergence of life. And by what intermediate stages did non-life become life? There is a monumental gap between inanimate matter and the most primitive life-form, bacteria, the simplest of which, mycoplasma, contains 470 genes. It’s a puzzle – so improbable that Francis Crick was forced to argue that it was born somewhere else, Mars perhaps, and came here via meteorite, thus making the mystery yet more mysterious.

How did life become sentient? And how did sentience grow to become self- consciousness, that strange gift, known only to Homo sapiens, that allows us to ask the question ‘Why?’ So many improbabilities had to happen that Stephen J Gould came to the conclusion that if the process of evolution were run again from the beginning it is doubtful whether Homo sapiens would ever have been born.

You don’t have to be religious to have a sense of awe at the sheer improbability of things. A few weeks ago James le Fanu published a book Why Us? In it he argues that we are about to undergo a paradigm shift in scientific understanding. The complexities of the genome, the emergence of the first multi-cellular life forms, the origins of Homo sapiens and our prodigiously enlarged brain: all these and more are too subtle to be accounted for on reductive, materialist, Darwinian science.

A week later Michael Brooks brought out Thirteen things that don’t make sense, the most important being human free will. The more science we learn, the more we understand how little we understand. The improbabilities keep multiplying, as does our cause for wonder.

And that’s just at the level of science. What about history? How probable is it that one man who performed no miracles and wielded no power, Abraham, would become the most influential figure who ever lived, with more than half of the six billion people alive today tracing their spiritual descent to him?

How probable is it that a tiny people, the children of Israel, known today as Jews, numbering less than a fifth of a per cent of the population of the world, would outlive every empire that sought its destruction? Or that a small, persecuted sect known as the Christians would one day become the largest movement of any kind in the world?

How probable is it that slavery would be abolished, that tyrannies would fall, that apartheid would end and that an African-American would be elected President of the United States? Everything interesting in life, the universe and the whole shebang is improbable, as Nicholas Taleb reminds us in The Black Swan, subtitled ‘The Impact of the Highly Improbable’. The book’s title is drawn from the fact that people were convinced that, since no one had ever seen a black swan, they did not exist – until someone discovered Australia.

The most interesting improbability of them all is that the man who invented probability theory, a brilliant young mathematician called Blaise Pascal, decided at the age of thirty to give up mathematics and science and devote the rest of his life to the exploration of religious faith.

Faith is the defeat of probability by the power of possibility. The prophets dreamed the improbable and by doing so helped bring it about. All the great human achievements, in art and science as well as the life of the spirit, came through people who ignored the probable and had faith in the possible.

So the bus advertisement would be improved by a small amendment. Instead of saying ‘There’s probably no God’, it should read: Improbably, there is a God.

by Chief Rabbi (UK) Sir Jonathan Sacks

[The following piece appeared in the Times of London late last month]