This essay, on how metaphors shape our thinking, was my Observer column this week. (The column included also a short piece on the miscarriage of justice over the Lockerbie bombing.) It was published on 15 March 2020, under the headline ‘Like a moth to a flame, we’re drawn to metaphors to explain ourselves’.

The selfish gene. The Big Bang. The greenhouse effect. Metaphors are at the heart of scientific thinking. They provide the means for both scientists and non-scientists to understand, think through and talk about abstract ideas in terms of more familiar objects or phenomena.

But if metaphors can illuminate, they can also constrain. In his new book, The Idea of the Brain, zoologist and historian Matthew Cobb tells the story of how scientists and philosophers have tried to understand the brain and how it works. In every age, Cobb shows, people have thought about the brain largely in terms of metaphors, drawn usually from the most exciting technology of the day, whether clocks or telephone exchanges or the contemporary obsession with computers. The brain, Cobb observes, ‘is more like a computer than like a clock’, but ‘even the simplest animal brain is not a computer like anything we have built, nor one we can yet envisage’.

Metaphors allow ‘insight and discovery’ but are ‘inevitably partial’ and ‘there will come a point when the understanding they allow will be outweighed by the limits they impose’. We may, Cobb suggests, be at that point in picturing the brain as a computer.

The paradox of neuroscience today is that we possess an unprecedented amount of data about the brain but barely a glimmer of a theory to explain how it works. Indeed, as the French neuroscientist Yves Frégnac has put it, making ample use of metaphor, it can feel as if ‘we are drowning in a flood of information’ and that ‘all sense of global understanding [of brain function] is in acute danger of being washed away’.

It’s not just in science that metaphors are significant in shaping the ways in which we think. In 1980, the linguist George Lakoff and philosopher Mark Johnson set off the modern debate on this issue with their seminal work, Metaphors We Live By. Metaphors, they argued, are not linguistic flourishes but the fundamental building blocks of thought. We don’t simply talk or write with metaphors, we also think with them.

It’s a view fiercely contested by other psychologists and linguists. But even critics don’t deny the significance of metaphors. There is an episode of Star Trek: The Next Generation in which the Starship Enterprise encounters an alien race called the Tamarians who speak only in metaphors and allegories. The Earthlings find it very difficult to communicate. Humans are not Tamarians. Nevertheless, there are few areas of life in which metaphoric use is not deeply embedded. Some studies suggest that one word in every 25 we use is a metaphor. And there is much evidence that the choice of metaphor can shape the way we perceive the world and act upon it.

In a series of experiments, two psychologists, Paul Thibodeau and Lera Boroditsky, gave participants one of two reports about crime in the fictional city of Addison. The reports were identical, except that in one crime was described as a ‘wild beast preying on the city’ and in the other as a ‘virus infecting the city’. When asked for solutions, those who read the first report suggested mostly tougher law enforcement and punishments, while those presented with the second were more willing to propose social reforms such as economic or healthcare improvements. Participants who identified as Republicans were 8-9% more likely to favour harsher punishment than Democrats. But the metaphor used made a difference twice as large – 18-22%. Metaphors, Thibodeau and Boroditsky observe, ‘have profound influences on how we conceptualise and act with respect to important societal issues’.

Social and political discussions are steeped in metaphors from ‘trickle-down economics’ to the ‘red wall’. They help frame the issues, and hence our responses, too. When politicians compare the national economy to a household budget, they are pushing us to think in particular ways about national debt or policies of austerity. Similarly, when politicians talk of ‘swarms’ of migrants or describe countries as ‘shields’ against them, the language aims to elicit particular public responses. The coronavirus is both a physical threat and a metaphor for everything from the failures of globalisation to the menace of foreigners.

The role that metaphors play in science and politics is subtly different. Many scientists accept that metaphors can be limiting, but insist, too, that they are an essential tool for thinking. In political and social debates, metaphors are primarily ways of framing issues, and of shaping the ways in which people think about them.

Metaphors can expand our vision and provide insights denied to more literal thinking. But, whether in science or in politics, we need to pay greater attention to the metaphors we wield.

The image is ‘Wired up’ by Inga Popesco, winner of the ‘Best Representation of the Human Connectome’ in the 2014 Brain Art competition.