The Precipice: Existential Risk and the Future of Humanity by Toby Ord. Hachette Books, 2020. 480 pp.
There is a question that most serious people do not take seriously: what is the probability that human civilisation ends within the next century? Toby Ord, a philosopher at Oxford’s Future of Humanity Institute, has spent a decade thinking about little else. The Precipice is the result.
The book’s central claim is striking: we have entered a period of unprecedented risk, in which the decisions made by this generation could determine not merely our own fate but the fate of all future generations. Ord estimates the probability of existential catastrophe this century at roughly one in six — the odds of a revolver with a single bullet.
Whether or not you accept that number, the book is a serious and important work.
The Argument
Ord begins by distinguishing between catastrophes and existential catastrophes. Ordinary catastrophes — wars, pandemics, economic collapses — are terrible, but humanity recovers. Existential catastrophes permanently destroy humanity’s potential. The distinction matters because the badness of an existential catastrophe is not just very large but qualitatively different: it forecloses all future possibility.
From this, a moral argument follows. If there are plausible scenarios that could end human civilisation, and if those scenarios are tractable — meaning we could reduce the probability with sufficient effort — then reducing existential risk is among the most important things we could do. The expected value calculation is staggering even on conservative assumptions.
We are like a teenager who has just got hold of a flamethrower. The power is real. The wisdom to wield it safely has not yet arrived.
Toby Ord, The Precipice
What Works
The book’s greatest strength is its intellectual honesty. Ord is careful to distinguish between what is known and what is speculative. He takes seriously the objections to his framework — the difficulty of estimating low-probability catastrophes, the risk of motivated reasoning, the cultural and philosophical assumptions embedded in his notion of “value.”
His survey of specific risks — engineered pandemics, misaligned artificial intelligence, nuclear war — is thorough and judicious. He neither catastrophises nor minimises. He is particularly good on the risk from advanced AI, which he regards as the most serious of the novel risks we face, and which he discusses with more care and nuance than most popular treatments.
The historical chapters, tracing humanity’s growing technological power against its slow-developing institutional wisdom, are among the best things in the book.
What Is Missing
The book has a certain philosophical thinness when it comes to questions of value. Ord assumes, broadly, that more human flourishing is better than less — that a future with many people living good lives is better than one with few or none. This is a reasonable assumption. But it is an assumption, and one that carries significant philosophical baggage that the book does not fully engage.
There is also a curious absence of politics. Ord writes as if existential risk were primarily a technical problem — amenable to better research, better institutions, better international coordination. This may be true. But the obstacles to international coordination on existential risk are not primarily technical. They are political, and the politics of catastrophic risk reduction are extraordinarily difficult.
A Necessary Book
These are relatively minor complaints about a book that is doing something genuinely difficult: taking the long-term future of humanity seriously as a subject of rigorous thought. Most serious people dismiss this as science fiction, or as the province of eccentric billionaires. Ord makes the case that it is, in fact, one of the most important questions of our time.
Whether he is right about the probabilities is uncertain. Whether he is right that the question deserves serious attention is, I think, beyond dispute.
The Precipice is the best introduction to existential risk thinking currently available, and one of the more important works of applied philosophy of the past decade.
Rating: Essential reading for anyone who thinks seriously about the future.