Before We Begin

This is a work of narrative nonfiction: a single story, told in order, from the first instant of the universe to a choice that has not yet been made. Everything in it is built from evidence, and the evidence is the point, so it seems fair to say a few plain words about how that works before the story starts.

Behind this book sits a research archive: several thousand documents, each one gathering what is actually known, argued, and disputed about a single subject, from cosmology to consciousness to the history of medicine. Every document in that archive rates its own claims on a simple scale. Some things are established beyond serious doubt: the age of the universe, the mechanism of natural selection, the sequence of the human genome. We state these plainly, the way you would state any settled fact, because dressing certainty up as tentative would be its own kind of dishonesty. Other things are credible but still argued among the people who study them. Others still are speculative: possible, worth taking seriously, not yet shown. A few are outright wrong, kept in view only because the wrongness itself is instructive. Where a claim in this book is more certain, or less certain, than that archive rates it, we say so, in the sentence where it matters, not in a disclaimer bolted on afterward.

We have tried to hold one discipline above all others: never to invent. No scene in this book is staged; no quotation is imagined; no specific detail has been added because it would read well. Where we describe a place, a moment, a person, the description comes from a real source, and where the sourcing runs thin we say that plainly too, rather than filling the gap with something that merely sounds true. Books like this one have gotten this wrong before, mistaking the color of good writing for the substance of good evidence, and it has cost them their credibility with the very readers who cared enough to check. We would rather be right and modest than impressive and caught out.

What follows, then, is not a new claim to have solved anything. It is a story about what the evidence, taken all together and in order, seems to add up to, and an honest accounting of exactly how sure we are, chapter by chapter, of each part of it. Where we say something happened, we mean the record shows it happened. Where we say something might be true, we mean exactly that, and no more. Where we don't know, and no one does, we will tell you so and keep walking anyway, because not knowing has never been a reason to stop asking.

One more thing, and then we will start. This book is written in the first person plural: we. Mostly that "we" is what it looks like: humanity, telling its own story back to itself, the way any of us might sit down with a friend and try to make sense of how we got here. It means something more than that too, but that isn't ours to tell you yet. You will understand why, and when, in time.

Thirteen billion, eight hundred million years ago, give or take, there was a beginning. Let's go and look at it.