The Irrational Decision: How We Gave Computers the Power to Choose for Us

by Benjamin Recht

How the computer revolution shaped our conception of rationality—and why human problems require solutions rooted in human intuition, morality, and judgment

In the 1940s, mathematicians set out to design computers that could act as ideal rational agents in the face of uncertainty. The Irrational Decision tells the story of how they settled on a peculiar mathematical definition of rationality in which every decision is a statistical question of risk. Benjamin Recht traces how this quantitative standard came to define our understanding of rationality, looking at the history of optimization, game theory, statistical testing, and machine learning. He explains why, now more than ever, we need to resist efforts by powerful tech interests to drive public policy and essentially rule our lives.

While mathematical rationality has proven valuable in accelerating computers, regulating pharmaceuticals, and deploying electronic commerce, it fails to solve messy human problems and has given rise to a view of a rational world that is not only overquantified but surprisingly limited. Recht shows how these mathematical methods emerged from wartime research and influenced fields ranging from economics to health care, drawing on illuminating examples ranging from diet planning to chess to self-driving cars.

Highlighting both the power and limitations of mathematical rationality, The Irrational Decision reveals why only humans can resolve fundamentally political or value-based questions and proposes a more expansive approach to decision making that is appropriately supported by computational tools yet firmly rooted in human intuition, morality, and judgment.

Genres: Nonfiction, Technology, History

280 pages, Hardcover

Published March 10, 2026

Reviews

[Jona · Rating 4 out of 5]

I have followed Ben‘s work and his blog for a while and generally enjoy reading his pieces, so I had high hopes going into this. The historical treatment was interesting and nicely complemented some other reading I have done lately on the history of computation. I also generally appreciated the effort of trying to show working as well as failure regimes of the methods and technologies that the books covers, and the book reinforced the perspective that I should freshen up my fundamental stats skills. That being said, I still finished the book being a bit unsure what to walk away with, apart from having ~geschärfte Sinne~ about what certain people market as rational (or optimal) solutions for problems that ought not have rational (or optimal) solutions. No revolution, but a reminder to stay skeptical, 3.5

[Catharina Kaylie · Rating 5 out of 5]

The Irrational Decision: How We Gave Computers the Power to Choose for Us by Benjamin Recht is a powerful and timely read that challenges how we define “rational” in a world increasingly driven by algorithms. Recht does an excellent job unpacking the history behind machine based decision making and exposing its hidden limitations. What makes this book stand out is its balance it doesn’t reject technology but instead urges us to question our blind trust in it. The examples are clear, relevant, and often unsettling, especially when applied to real-world systems like AI and public policy. By the end, you’re left rethinking not just computers, but your own decision-making process.

[Kent E. Holsinger · Rating 5 out of 5]

The limits of mathematical rationality

For the last 80 years a mathematical approach to rationality has dominated economics and many other fields. Computers are very good at optimization when problems are well defined, i.e., the boundaries of acceptable solutions are clearly specified and there is a clear definition of what “optimal” means. But many of the problems that face us are ill-defined and the choice among competing definitions is a choice among different value systems. Computers can decide, but they can’t choose. To understand why, read this book.

[Paul · Rating 3 out of 5]

I expected it to be about the limits of being able to delegate decision making to AI based on either impossibility of transfer of responsibility or fundamental inability to articulate requirements (because they are contradictory or unknowable beforehand). Instead it tried to make a more trivial objection about technical limits. Technical limits are temporary.

Spends almost half the book on science history that is not relevant to the arguments. Better treatments of it available in many other books. Why not just put some in suggested reading and the concentrate on the argumentation?

[James Hennessy · Rating 3 out of 5]

learned some history I didn't before but seems more about behavior economics than computers