Nullius in verba: the motto of the Royal Society

Machine Logic

At the junction of computation, logic and mathematics

17 Jun 2026

general

philosophy

Nullius in verba (“take nobody’s word for it”) is the motto of the Royal Society, and as they explain, is “an expression of the determination of Fellows to withstand the domination of authority and to verify all statements by an appeal to facts determined by experiment.” At first glance, this motto is wildly hypocritical: why then does the Royal Society promote meetings and lectures? Why does it publish journals? It’s true that back in its early days (the 17th century), one could do actual science at a meeting. You could turn up with a new type of telescope, microscope or prism and demonstrate its use then and there. Such things are hardly possible now: modern science is a vast body of knowledge, derived from thousands of years of observations, these days done with equipment that few of us will ever even see. The distrust expressed by the motto seems appropriate for our sceptical age, where people assume that scientists have been bought or inhabit nothing but an elaborate belief system.

“Trust no one”

That is the tagline of the typical Hollywood thriller. The hero of such a movie will have a terrible time and will be lucky to be alive at the end. We trust others with our every interaction, and even the mighty eagle, an apex predator, still has to trust its own mother during infancy. Civilisation is impossible without trust. We trust the people we meet based on cues such as who they are, how they look, how they speak and what they say and do. In our interactions, we strive to earn trust by behaving appropriately and keeping our promises. Once lost, trust can seldom be regained.

But there are people who will not be convinced, no matter what you do. The recent COVID-19 pandemic is a striking case in point. To my mind, the scientific community responded brilliantly: from a standing start, confronted with a pathogen no one had seen before, they needed just a couple of years to achieve a deep understanding of the disease. They developed treatments to cure it and vaccines to prevent it. But many people saw something very different: shifting advice and draconian lockdowns coupled with scepticism that the disease even existed. Another example: due to the link between cholesterol and heart disease, people were for decades advised to avoid eggs and butter. We were encouraged to eat margarines made of polyunsaturated fat, which later were discovered to have their own risks while 1–2 eggs per day were shown to be safe. Scientific advice constantly changes, sometimes drastically. What can we do?

“When the facts change, I change my mind. What do you do, sir?”

There is no proof that John Maynard Keynes ever actually said this. But whatever, it is hard to argue with the sentiment. In science we accept that we can never attain the truth, just increasingly close approximations to it. Prevailing theories change as we learn more, through observations or experiments. We went from the Earth at centre of the universe to the Sun at the centre, then we were one solar system in a galaxy, then there were countless galaxies. We went from atoms as ancient philosophy to a series of atomic models based on experimentation: the billiard ball model, the plum pudding model, the solar system model and progressively to the quantum-mechanical model used today. So was everybody wrong? The models captured the existence of atoms, then their composition from protons and electrons; the existence of neutrons was conjectured before they could be observed and the behaviour of electrons inferred from a great many considerations, such as the periodic table.

With both examples (cosmology and atomic theory), one can argue that scientists have been wrong for most of human history. But each of their conceptions had merit, and as we progressed from one to the next (whether incrementally or radically), they became more accurate and useful. Every scientific model is an abstraction of reality. Even if we could capture reality with perfect accuracy, no amount of experimentation could prove that we had done so.

And yet. Can anyone doubt that scientific theories have repeatedly demonstrated their effectiveness? We have been to the moon; we have accomplished miracles through modern medicine; we’ve built astonishing electronic devices; above all, our understanding of the atom has demonstrated its devastating power. If you are reading this and are not sitting next to me, you cannot deny the power of science.

Making your own observations

Modern physics emerged from countless experiments involving particle accelerators, cloud chambers and other esoteric devices. Chemistry, biology and other sciences also developed through centuries of laboratory work. You can’t try such things at home. Marie Curie died as a direct result of her research, and she is far from...

Nullius in verba: the motto of the Royal Society

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