When I was about 7, I used to go fossicking for fossils on Dorset's Jurassic Coast. I collected ammonites and belemnites, gleefully hoarding them in a tiny cabinet of curiosities alongside nuggets of fool's gold and coprolites.
Like most small boys I was obsessed with dinosaurs and all things prehistoric. I also remember being struck by the well-known analogy of the "geologic clock", in which the Earth's history is compressed into a day. On this measure Homo sapiens only left Africa two seconds before midnight, and all of human history is crammed into a 10th of a second.
This was probably my earliest encounter with a scientific analogy, and it made an impression. A steady diet of Willard Price animal adventures and hard science fiction led me inexorably towards an interest in science, culminating in degrees in molecular biology and psychology.
As a science writer, analogy is one of my most important and powerful tools, but the profound role of analogies in science did not really come to my attention until I was working on a biography of Isaac Newton, which in turn led to a book about scientific feuds. The science I encountered in these books, and the history of that science, foregrounded the power of the analogy, which has formed and guided scientific thinking since the start of the early modern period.
Analogous reasoning has inspired and underpinned many of the great breakthroughs in science, from Johannes Kepler seeing the cosmos as a great clockwork mechanism to Newton's comparison of the fall of an apple with the motion of the Moon, and from August Kekule arriving at the annular structure of benzene through his dream of a snake biting its own tail to Albert Einstein conceiving the theory of relativity through a thought experiment about travelling on a beam of light. I also learned how analogy can mislead and distort, from the teleological fallacy of William Paley's watch on the heath to the miscasting of Charles Darwin's tree of life as the evolutionary ladder, with its grim codas of white supremacy and eugenics.
All these analogies and more were the inspiration for my book A Bee in a Cathedral. It presents a wide array of analogies illustrated with trivia and infographics, so that a reader can look for illuminating explanations of difficult concepts, pick up interesting titbits with which to bother dinner party guests, and discover unfamiliar topics and new ways to think about familiar ones.
Compiling more than 100 analogies and thought experiments was a considerable challenge. I raided sources far and wide for inspiration and even came up with a few of my own. My jumping-off point was an invaluable teaching guide, Using Analogies in Middle and Secondary Science Classrooms by Allan G. Harrison and Richard K. Coll, and certainly one aspiration for my book is that it could serve as a useful resource for students and teachers. This is especially true of the analogies that I feel have the greatest explanatory power, such as the Coriolis effect being like throwing a ball on a carousel, or the bush as a superior illustration of evolutionary history.
Admittedly there were some challenges, such as compressing analogous illustrations of the twin paradox or Einstein's principle of equivalence into just a few hundred words. But there were also many moments of fascination and revelation, from discovering that the copepod is the mightiest creature in creation to learning the calorie content of an average ejaculation. Best of all, I have included some of my favourite thought experiments, such as the wonderful Ship of Theseus paradox, guaranteed to spark discussion and debate whether the book is read in the classroom or on the loo.
Joel Levy is a writer and journalist specialising in science and history. He is the author of more than a dozen books. A Bee in a Cathedral is published by Firefly Books
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