You may have recently read about many of the topics covered in On the Edge on the blog Marginal Revolution or similar publications: tech founders, large language models, effective altruism, Sam Bankman-Fried, existential risk. If you recognize those names and phrases but are sketchy on the details, read this book right now because it will be useful. But the topics it covers may not be relevant in a few years, as On the Edge is very much a product of the period 2021–2024.

River and Village / In describing common economic thinking and response to risk, Silver divides people into two groups: “The River” and “The Village.” Folks who make up The River combine extreme risk neutrality (or even risk-seeking behavior) with the prowess of a natural economist. (Those are not the exact words he uses, but you know such people.)

People who are part of The River fall along a spectrum of ability, from being a marginally functional member of society, to living somewhat respectably, to being among the elite. At the low end are degenerate gamblers and con artists; going “up” The River (i.e., progressively less degenerate and more professionally successful), you find successful gamblers, crypto enthusiasts, narcissistic traders on Wall Street, provocative utilitarian philosophers, and tech founders.

Opposing them in the post-COVID world is what Silver calls The Village. Members are a collection of high achieving journalists, academics, and professionals whose politics have skewed increasingly left. An earlier generation may have called them “the chattering class” or “pearl-clutchers.”

Interpreting The River / The first third of the book serves as a bridge between The Signal and the Noise—Silver’s statement on Bayesian reasoning and the best practices for prediction—and the topics covered in On the Edge. He does this via an anthropological journey through the world of professional gambling, which he had covered a bit in his earlier book.

In On the Edge, Silver chronicles how the same analytical revolution that occurred in baseball, to which he was a key contributor, swept through professional gambling a few years later, where he is a minor figure today. He tells the history of Las Vegas, broadly outlines the best techniques for playing poker, and opines on various controversies and policy issues related to gambling. Most controversially for economists, he makes the case for why many sports betting lines can be rather inefficient at reflecting the “true” odds of a team winning.

Following the chapters on professional gambling, there is a brief interlude where Silver seeks out other members of The River in various fields where one may not expect to find them. Perhaps this is the natural economist in me, but the numerous interviews of such people throughout the book bog down an already lengthy work and do not add much. Of course, a reader from The Village would likely disagree with me.

Following that interlude is the most noteworthy of the book’s interviews: a series of lengthy conversations with Sam Bankman-Fried that forms the backbone of the latter portion of the book. But even here, will anyone in 2030 remember Bankman-Fried? Have you already forgotten who he is? On the Edge is very much a product of the time in which it was written.

If you have forgotten him, Bankman-Fried was the youthful head of an intertwined hedge fund (Alameda) and cryptocurrency exchange (FTX). Much of the latter half of the book tells of his downfall, with Silver recounting interviews prior to, during, and after it. Bankman-Fried ended up with a prison sentence of 25 years for illegally using investor deposits as funds to toy with financial markets in a manner that would make professional poker players squirm. He made trades that were, in effect, “fifty percent I destroy all my wealth and go to jail, fifty percent I double my money plus a dollar.” Positive expected value, Bernoulli be damned.

The story of Bankman-Fried, both in real life and in Silver’s account, seamlessly serves as a critique of the utilitarianism of Peter Singer and the “effective altruism” of William MacAskill, an outgrowth of Singer’s philosophy, which got caught up with (and was substantially funded by) Bankman-Friedman in the early 2020s. Effective altruism was “supposed to be” boring philanthropic recommendations like buying mosquito nets to save the most lives per dollar spent. At its more provocative, it would tell people to work more hours at their day job rather than volunteering, so they could give more money to effective charities.

But effective altruism became associated with embarrassments like Bankman-Fried appearing on Tyler Cowen’s podcast, Conversations with Tyler, during which Cowen got him to agree to continuously flip coins where the number of Earths doubles (and therefore utility doubles) with 51 percent probability and all life ceases to exist with 49 percent probability, because that would result in positive expected value. Silver mentions this episode in the book, and I distinctly remember listening to it while doing dishes the night it was published. I metaphorically heard a record scratch when listening to Bankman-Fried make this claim.

What Silver is ultimately intending throughout the second part of the book is to play the public’s interpreter of Bankman-Fried, Elon Musk, cryptocurrency, effective altruism, and whether artificial intelligence will one day kill us all. All these issues are ones directly related to the interests of The River, and it is the real meat of the book. Silver then offers sensible, generally middle-of-the-road conclusions on most of the issues raised. But what makes the book especially useful is that it gives you a rough (if troubling) idea of how some of your neighbors see the world and operate in it. Silver is terrific in clarifying that.

Conclusion / The concluding chapter is a somewhat surprising ode to classical liberalism and Pinkerite optimism through the lens of Deirdre McCloskey. (In fairness, Silver has shown these sentiments before, including in a Reason podcast months before the book was published.) Of notable interest is his call for pluralism—as Silver defines it, preventing any single group or ideology from dominating.

I have a speculative and Straussian reading of this oddly placed conclusion. Sports analytics and the organization Baseball Prospectus were where Silver first came to prominence and were the first place for The River to go mainstream and take over culture. But in the last 10 years, these organizations have become colonized by The Village, with all that entails. Perhaps with a bit more emphasis on pluralism, those organizations could have stayed in The River and continued to generate insights.