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Nullius in verba

Often translated as ‘take nobody’s word for it’, this is the motto of the Royal Society. It nicely encapsulates the basic critical outlook expected of scientists; in effect, listen to others but come to your own conclusions. Scientists, by nature and training, should be both curious and sceptical. They should be seeking to discover, but also continue to question their conclusions in the light of new evidence.

Non-scientists often think that scientists deal in facts and certainties, but this is a misrepresentation. All the evidence may support a certain hypothesis, but this can in principle be called into question by a single reliable and reproducible observation. This is sometimes described by the black swan metaphor: ‘all swans are white’ remains a true statement until a black one is seen. In this sense, all scientific knowledge is provisional. It remains out best understanding of reality until we find out more.

Some things so obviously conform to certain patterns that they can be described by scientific laws, such as gravity. But other things may be generally accepted as true but are perhaps only the best description we have at that point. For example, we still refer to the theory of evolution, despite the fact that all the evidence from fossils and current observations supports the fact that life evolved from a common ancestor and adapted to specific ecological niches. A more subtle case is that of Newtonian mechanics, which perfectly describes the behaviour of moving objects on Earth, but is supplanted by the theory of relativity for bodies moving extremely fast.

The Royal Society was set up in the 1660s, in the reign of Charles II, but was not the body it now is. Sir Christopher Wren gave a lecture that is credited with catalysing the Society’s formation, and its early members included not just eminent scientists such as Isaac Newton and Robert Hooke, but also other people with a broader interest in discovery. For example, Samuel Pepys was its President for a time.

Today, the Royal Society is comprised of a body of elected Fellows, all eminent scientists. It rewards demonstrable achievement and is the core of the scientific establishment. Unfortunately, ‘nullius in verba’ no longer seems to be its guiding principle. Michael Kelly, Professor of Engineering at Cambridge University, and himself a Fellow of the Royal Society, makes this plain in a recently published paper, Lessons from technology development for energy and sustainability.

The very important point made is that the technologies being deployed to radically reduce carbon dioxide emissions as a response to the supposed impacts of projected changes to the climate are inadequate for the task. Professor Kelly argues that a rethink is necessary: assumptions on the range of likely impacts of climate change – positive as well as negative – need to be checked and the possible effects of taking action weighed against doing nothing at present.

For many, questioning the assumption that this is a real problem which, given sufficient resources, is currently soluble, is simply unthinkable. The IPCC, politicians and the scientific all sing from the same hymn sheet; the trajectory of average temperatures is such as to give a high chance of ‘dangerous’ changes this century and decarbonisation of the world economy is the only way to reduce the risk.

However, the scale of the task is immense: the UK is proposing to cut its emissions by 80% against a 1990 baseline by 2050. Even then, looking at the achievement so far makes it plain that actions taken in recent decades have not addressed the overarching issue of total global emissions. To quote from the paper: “While the UK prides itself in reducing indigenous carbon dioxide emissions by 20% since 1990, the attribution of carbon emissions by end use shows a 20% increase over the same period”.

A further illustration puts the current push towards renewable energy in perspective:

“Today, geothermal, hydro- and nuclear power, together with the historic biofuels of wood and straw, account for about 15% of our energy use. Even though it is 40 years since the first oil shocks kick-started the modern renewable energy developments (wind, solar, and cultivated biomass), we still get rather less than 1% of our world energy from these sources. Indeed the rate at which fossil fuels are growing is seven times that at which the low carbon energies are growing, as the ratio of fossil fuel energy used to total energy used has remained unchanged since 1990 at 85%.”

This is a viewpoint that is at odds with the received wisdom and, in particular, with the official line of the Royal Society. At one time, the Society may have encouraged debate and accept such views as worth considering. Unfortunately, this is no longer true. “The one change from history is that a bylaw of the Society that stood for most of its history has been overturned in recent decades. Whereas once ‘ is an established rule of the Society, to which they will always adhere, never to give their opinion as a body upon any subject either of Nature or of Art, that comes before them’, now the Royal Society plays an active role in the debate, coming at it from only one side, without adequate acknowledgement of the lack of unanimity within the fellowship”.

The truth about climate change will continue to evolve and be the subject of intense debate for many years yet. Scientists have a central role in collecting and assessing the evidence for particular hypotheses. Such controversy should be encouraged rather than effectively banned.