Occam’s razor: The medieval monk who saw the power of simplicity

William of Ockham was tried for heresy before the Pope, only to make a daring escape. His big idea, known as Occam’s razor, remains the keenest tool for honing our understanding of the world

By Johnjoe McFadden

ON MY daily drive into work at the University of Surrey, I pass a road sign to Ockham. Perhaps a slight difference in spelling is one reason why it took me a surprising while to realise the English village’s connection to one of the most fundamental concepts in science – I would argue, in my now more enlightened state, perhaps its most fundamental concept.

I am talking about Occam’s razor. The creation of a 14th-century theologian with a racy life story, this is a principle often quoted as “entities should not be multiplied beyond necessity”. It urges us to choose the simplest explanations or models for any phenomenon we observe. If you see moving lights in the night sky, say, think of known existing entities such as aeroplanes, satellites or shooting stars before considering flying saucers.

It has been a tool for scientific progress, not to mention a guiding principle for our own thoughts, right up to the present day. But I believe that modern science has rather lost sight of the simple fact that simplicity is the sharpest guide to greater truths.

Ockham is linked to Occam’s razor by virtue of William of Ockham. Born in the village around 1285, William went to a local Franciscan school before being sent to Oxford to study theology, then known as “the Queen of Sciences”. This title was largely due to the influence of Italian theologian Thomas Aquinas, who had recently Christianised the work of the greatest scientist of ancient Greece, Aristotle.

That mind-meld had supplied five scientific “proofs” of the existence of God, a variety of metaphysical essences of reality known …