EARLY PRAISE FOR
THE SCIENCE OF WHY WE EXIST
“This is the Outline of History that H. G. Wells would have written if he’d lived now rather than then. Most scientists know only their own field. Tim Coulson is at home with science as an integrated whole. A pleasure to read, and a lasting accomplishment to have written.”
—Richard Dawkins, author of The Genetic Book of the Dead
“Exceptional. A highly infectious read. From the first page I found it impossible to put down. An erudite, witty, and highly intelligent romp through the history of life as we know it.”
—Professor Kathy Willis, professor of biodiversity, University of Oxford, and author of Good Nature
“Achieves something almost impossible: lucid explanation without dumbing down. I would defy any scientist not to read this and learn something. For those with no science beyond the stuff at school which you hated, the author hated school too and has you covered. You can read this for fun and accidentally you will know as much general science as any professor.”
—James H. Naismith, head of the mathematical, physical, and life sciences division, professor of structural biology, University of Oxford
“A gangbuster science book. A can’t-put-down read. I don’t think I have learned more from a single book.”
—Douglas W. Smith, former senior wildlife biologist, Yellowstone National Park
“Tim Coulson’s book is a ripping yarn about the history of our improbable existence. It is fundamentally factual, with every inference evaluated in the context of the scientific method, highlighting the continuity of the thread across vast time scales that span physical, chemical, and biological events that led to who we are today. It is smart, informative, yet approachable and brimming with personal anecdotes and humor.”
—Rosie Gillespie, professor of environmental science, policy, and management, University of California, Berkeley
“Step aside Star Wars—ours is the most astonishing story you’ll ever hear and it is beautifully told by Tim Coulson.”
—Professor Ken Norris, deputy director of science, Natural History Museum
“An extremely enjoyable read, written in a very engaging way, and sprinkled with often very funny anecdotes. Will appeal to a broad variety of readers and inspire new generations of scientists for years to come.”
—Quentin Paynter
“A charming, engaging and erudite account by a distinguished biologist of all the things that had to happen for you and me to exist and be as we are.”
—David Christian, author of the New York Times bestselling Origin Story
“What have we learned about the past 13.8 billion years that resulted in you looking at this book? Tim Coulson, a fun scientist who has no limits to his brain’s boundaries takes us on a free spirited intellectual romp through every aspect of what we know about our universe. A highly readable and super enjoyable book.”
—Peter Hudson, FRS, Willaman professor of biology, Penn State
“I learned a lot from this fantastic book on the history of the universe, as will anyone who reads it. In writing this easy-to-read and highly enjoyable book, evolutionary biologist Tim Coulson places himself amongst the very best science communicators.”
—Nils Chr. Stenseth, professor of ecology and evolution, University of Oslo, member of the US National Academy of Sciences, and former president of the Norwegian Academy of Science
For Sonya, Sophie, Georgia and Luke
‘Contemplate the marvel that is existence, and rejoice that you are able to do so. I feel I have the right to tell you this because, as I am inscribing these words, I am doing the same.’
– Exhalation by Ted Chiang
Introduction
If I could be a god there would be no flashy miracles, but there would be lots of universes. Enough universes to enable a scientist like me to conduct an ambitious experiment – an experiment that I, and I’m sure many others, dream of. I would like to identically re-create the conditions at the instant our universe came into being, run the clock forward, and examine how many of the resulting universes develop to become a home for you and me.
I would ensure that each starting point for each of my universes was identical. After 13.77 billion years, the age of our own universe, I would head to where our solar system should be in each of my experimental replicates. If our solar system was there, I would search out Earth before looking for you and me. Would we always be there, just as we are today? Or would we only be there in a few of the universes? Or in none at all? Would little green aliens with giant ears and no noses sometimes be in our place? On some occasions perhaps there would be no sign of our sun or the Earth at all, or maybe the Earth would be barren, moonless and devoid of plants and animals, circulating too far from the sun for life to flourish. In some universes life may be abundant, in others it might be rare, or even entirely absent. As far as we know, we are the only planet with life in our universe, although we have only explored a very tiny part of it.
My experiment would reveal whether the history of our universe was set at its birth or whether each replay produces a different outcome. If each play of the tape produced you and me, scientists would describe the universe as being deterministic. With hard work and a huge amount of computing power, we could perfectly predict the future of any universe from its birth until its end. Some physicists have argued that this is what would happen if the experiment I describe was run. They believe that physics will one day reveal that things we currently think are random, including the behaviour of tiny particles, will be shown to be deterministic. In contrast, if each outcome was different, as most biologists and many other scientists believe, then that means random events have influenced the development of our universe. A random difference in the history of each universe could result in very different outcomes. Perhaps if the asteroid that killed the dinosaurs had passed by Earth rather than hitting it, humans might never have evolved and an intelligent species of dinosaur might be writing a book like this instead of me.
Scientists describe universes where chance events make it impossible to accurately predict the future as being stochastic. If random events do play a role in the history of our universe and our existence, we will not be able to perfectly predict the future, but this does not mean there is no predictability. If we were to monitor 1,000 universes in my rerun experiment, perhaps intelligent life would arise 531 times but fail to evolve on 469 occasions. If you placed a wager on intelligent life evolving at the Betting Shop at the Beginning of Time, you would have just over a 50 per cent chance of winning that bet. With odds of a little less than two-to-one, if intelligent life did eventually evolve, you would win twice as much as you originally bet.
Sadly, I am not a god, and we do not have the know-how to run my thought experiment to assess whether the universe is deterministic or stochastic. Creating new universes on a whim, and studying their evolution, is beyond our technical expertise. Therefore, answering the question of whether you and I were inevitable at the birth of our universe, or if we are just incredibly lucky, requires another approach: science that we can do. This book aims to tell two stories in parallel. The story of the universe from its birth until you and me; and the story of what had to happen for you and me to exist. These stories are a 13.77-billion-year epic. They involve unimaginable violence, death and a lot of sex, and although they often read as a tragedy they are ultimately a story of success. The sleuths who have slaved to piece together the stories of why you and I are alive (and know it) are more imaginative and cunning than Miss Marple, Sherlock Holmes, Nancy Drew and Hercule Poirot combined. They count among their number Albert Einstein, Marie Curie, Isaac Newton, Rosalind Franklin and Charles Darwin, and thousands of others of whom you will likely have never heard. The story is a work in progress, and the plot is subject to edits as brilliant minds continue to solve more of the mystery of why I am me, and you are you. However, even the incomplete script is sufficiently awe-inspiring to be a story that everyone should know.