When guiding us through the use and misuse of some the most important metaphors in the life sciences, Reynolds exhibits a deep understanding of both the science of metaphor and the science of life, a combination of expertise that is quite rare and immensely valuable.

Science tries to understand the world we live in. To understand science and how it works, we have to get to grips with some of the methods it uses, from maths to … metaphor. Metaphor is not only one of the most important conceptual tools we use to live by, but also one of the most important conceptual tools we use to do science by. In this book, Reynolds explores and explains the use of metaphors in the life sciences. This is especially important as the life sciences shape the meaning of life and our ways of living and dying.

When guiding us through the use and misuse of some the most important metaphors in the life sciences, Reynolds exhibits a deep understanding of both the science of metaphor and the science of life, a combination of expertise that is quite rare and immensely valuable. Readers who don’t have their feet in both fields will have to be patient in places but are richly rewarded.

The book starts with a succinct introduction to old and new thinking about the role of metaphors in science. One contribution, from the philosopher Mary Hesse — the distinction between positive, negative and neutral analogies that structures metaphorical mappings in science — is used throughout the book. So too is the distinction between metaphors as heuristic, cognitive, and rhetorical/communicative/pedagogical devices — well-known distinctions to which Reynolds adds another extremely important one, namely metaphors as “technological instruments that assist scientists in manipulating and bringing about real material change to the objects of their study”.

Reynolds makes clear that far from being mere decorative devices, metaphors are more like scientific hypotheses. They are always partial and provisional and need to be kept under constant scrutiny and revised when new evidence emerges. They are, I would add, similar to models in being mostly wrong but sometimes useful. When mapping knowledge from a familiar source onto an unfamiliar target, the match is never perfect. There is always a crack. That’s where the light gets in, as Leonard Cohen would say; that’s where science happens.

The introductory chapter is followed in Chapter 2 by an overview of what one may call basic metaphors in the life sciences, such as agent, machine and information metaphors. Some other metaphors, such as trees, streams and landscapes, are also mentioned, as they are important to certain fields in the life sciences. Chapter 3 then deals with metaphors that structure how we talk about genes and genomes in terms of agents, codes, programs, blueprints and books (of life).

As genes make proteins, Chapter 4 examines protein metaphors, such as machines, messengers and, more novel perhaps, team players. All this takes place inside cells which have a long metaphorical history in terms of factories, computers and social organisms, also explored in Reynolds’s seminal book The Third Lens: Metaphor and the Creation of Modern Cell Biology (2018); and the word ‘cell’ itself has a long and fascinating history. Chapter 5 deals with cell metaphors in detail.

Chapters 6, 7 and 8 focus, in turn, on evolution (natural selection, the tree of life, and, importantly, selfish genes, a metaphor that continues to create confusion and controversies), ecology (the balance of nature, niches, ecosystem health and Gaia) and finally biomedicine (genetic engineering, genome editing, and cell reprogramming). This chapter highlights “the performative effect of metaphors to prescribe certain avenues of research and interventions”, for good or for ill. The chapter deals with issues which are also discussed in the forthcoming book by Matthew Cobb, The Genetic Age: Our Perilous Quest to Edit Life (2022). Both authors are experts at weaving together the history of science with the history of language and culture.

In the 19th century, words were conceptualised as living organisms; in the 20th century, living organisms were conceptualised as words (writing, information, code). When linguistics emerged as a discipline, it borrowed some of its metaphors from biology. When molecular biology and genetics emerged as disciplines they borrowed some of their metaphors from linguistics and allied sciences. Both biology and linguistics emerged at a time of industrial, technological and societal change and were influenced profoundly by these changes. Linguists and biologists met in Paris in 1968, amongst them Roman Jakobson, the linguist, and François Jacob, the molecular biologist. Now, more than half a century later, we have a book that both scholars would have loved to have on their shelves.

This book is written in an accessible style which makes it a joy to read. It is essential reading for anybody interested in the life sciences and how these sciences and their public understanding are shaped by metaphor. The only quibble I have is with the printing: the small font makes it almost inaccessible to older readers.