In our schooldays, most of us knew of William of Occam and his razor, but few of us knew why we knew, and fewer still knew what it was the famous razor was supposed to shave, other than its owner’s beard.
Johnjoe McFadden’s sweeping subtitle, How Occam’s Razor Set Science Free and Unlocked the Universe, will startle many a reader possessed of no more knowledge of the subject than us chislers of yesteryear. However, his thoroughly fascinating book goes a long way to justifying his claims.
There is no one acknowledged definition of Occam’s razor, and the man himself stated his thesis in various forms, the pithiest of which McFadden quotes as “it is futile to do with more what can be done with less”. In other words, if other words are needed, stick to basics and don’t complicate matters. It seems a simple piece of advice, and so it is. But as McFadden suggests, the application of Occam’s razor “underpins the modern world”.
William of Occam, or Ockham, was born in the village of that name, in Surrey, to the south of London, in 1287. He studied theology at Oxford, did not take a full degree, but went on to become a Franciscan friar, and one of the leading figures in Medieval philosophy.
The ignorant frequently refer to Occam’s era as the Dark Ages, but in fact those centuries glowed with a steady light, even though not a little of it was generated by the bodies of “heretics” burning at the stake. Occam himself might have died in that terrible fashion, if Pope John XXII had got his hands on him.
McFadden opens his book with an account of Occam’s night-time escape from Avignon, where the pope resided at the time, to the walled port city of Aigues-Mortes in the Languedoc region of southern France, and onwards. These few pages are worthy of Walter Scott or Robert Louis Stevenson at their most vivid. Three monks, including Occam, were fleeing papal wrath after Occam, accused of heresy on an obscure point of religion, in turn had branded Pope John himself a heretic. Surviving a number of hazards, Occam at last found refuge at the court of the Holy Roman emperor, who at the time was in dispute with the papacy.
Occam had first got into trouble by denying Thomas Aquinas’s contention that theology is the Queen of Sciences. Not only is it not the queen, Occam insisted, it’s not even a courtier. For Occam, God is all-powerful and unknowable, and mortals have no business trying to poke at Him, or It, with their theories and hypotheses. As McFadden writes, “Occam used his razor to strip away everything in medieval philosophy except God’s omnipotence.” This may be to overstate the case a little – everything? – but we take the point.
McFadden gives fair due to many of the great minds who have contributed to our present state of knowledge
Theology, Occam suggested, is free to speculate till the cows come home. On the other hand, science, which is carried on by mortal beings, can only know what it knows and what it continues to uncover, and there’s an end of it.
This separation of theology from science – or natural philosophy, as it was then called – is what permits McFadden the first half of his subtitle. Occam argued against the philosophical realists in their belief in the existence of Platonic “forms” or Aristotle’s “universals”. In their terms, a father is a father because he is imbued with the universal condition of “fatherness”. Not at all, said Occam: a father is a father because he has a child.
This is an instance of the Occamist “principle of parsimony”; McFadden writes that “with one stroke of his razor, William dismissed the vast thicket of entities that cluttered the philosophy and science of the medieval world and the world suddenly became immensely simpler and a lot more comprehensible . . . In Occam’s logic, devoid of universals and filled only with individuals, the only way to gain sure knowledge is through experience and observation. This is, of course, the cornerstone of modern science.”
At the start of his long journey from medieval philosophy to the outermost reaches of today’s quantum speculations, McFadden quotes a key remark made in 1934 by one of the founding fathers of modern physics, if not the daddy of them all, Albert Einstein: “The grand aim of all science [is] to cover the greatest number of empirical facts by logical deduction from the smallest possible number of hypotheses or axioms.” This is essentially a restatement of Occam’s razor.
McFadden, born in Donegal but brought up in England, is professor of molecular genetics at the University of Surrey, which is not far from Occam’s birthplace. Most of his work has been carried out in the science of medicine, concentrating on the part that microbes play in diseases such as meningitis. However, far from being a narrow specialist, he has a firm grasp of the complexities of many branches of science. His account here of the evolution of astronomy from the dreams of the stargazers of the ancient world to the latest theories on black holes is breath-taking in its comprehensiveness and clarity.
Along the way he gives fair due to many of the great minds who have contributed to our present state of knowledge. Notable in particular is the attention he devotes to those who have been side-lined or forgotten. These include Emmy Noether, the German mathematician who, being a woman, was repeatedly refused a professorship in German universities yet is regarded today as one of the great speculative geniuses of all time. She was also a splendid human being; one of her male colleagues described her as “warm, like a loaf of bread”.
And then there is Alfred Russell Wallace, who hit on the theory of natural selection at the same time as Darwin, but whose originality is hardly recalled in public memory. This is particularly ironic, since one of the most daring and inventive theoretical physicists of our time, Lee Smolin, has suggested that black holes might be regarded as the reproductive cells of an infinitely self-replicating universe.
The consequence of this astonishing hypothesis is that, as McFadden writes, “the fundamental law of the universe is not quantum mechanics, or general relativity or even the laws of mathematics. It is the law of natural selection. . .” Nature moves in mysterious ways.
John Banville’s latest novel, April in Spain, is out next month
