Irrationality: The Enemy Within by Stuart Sutherland. Too true.

Penguin, 1994, 357 pages.

Well. This book is replete with summaries of studies that on the whole show that we are creatures of habit, instinct and fear more than thought and reason. We suffer from the illusion of control. We make emotional decisions and then convince ourselves they were carefully reasoned. We avoid data that might prove us wrong, even when being proved wrong is the best thing that could happen to us.

The cover of <i>Irrationality</i> by Stuart Sutherland.

The cover of Irrationality by Stuart Sutherland.

I can’t say I was shocked. There’s a time and a place for aiming for the utmost in rationality, of course, and times when that’s not sensible, and it is useful to know the difference. If you’re being chased by a bear a quick but sub-optimal decision may be better than making the right one too late. And it’s useful to know when it doesn’t really matter and you can just please your inner reptile, and when you really do need to sit down and analyse things properly.

And in a sense that is the key point. He basically says that only by understanding statistics and by essentially falling back on some means of scoring the alternatives and then picking the one with the best score can we really make rational decisions. Otherwise we rely on impressions, feelings and hunches, none of which are actually reliable. In the end, only by breaking down the problem and applying some kind of rigorous-as-possible analysis, generally relying on mathematics, can a really rational decision be made. And what fraction of decisions are made like than? In my life, relatively few.

Each chapter tackles various forms of irrationality, and each ends with a ‘moral’ which is really a bullet-point summary, the last one of which is usually humorous/facetious. (‘Eat what you fancy.’)

There is some repetition, but the points being made deserve hammering home. There are some lovely little ‘try this yourself’ puzzles, where even though I knew there was a trick and I desperately did not want to answer like an irrational creature, I still got it wrong. The simple two card trick, for example, which I won’t describe in detail here since it would be too much like giving away the twist in the tail.

In summary, if you think you are good at making decisions, you might find this book useful. If you already believe that we’re basically animals in clothes, this will not disabuse you. It’s funny, opinionated, amusing and entertaining, but a little, I repeat, repetitive. Some of the case studies of how really really really important ‘decisions’ were made are a little worrisome, especially because (of course) human nature has not really changed in the meantime. I sometimes look around at a skyscraper, or read about a decision to go to war or spend billions of dollars on a useless aeroplane, and this book comes to mind. Will the building fall down? Is the war really worthwhile? Will the aeroplane get off the ground, and if it does will it stay up?

In some ways the book makes our achievements all the greater. Okay, the planet is in trouble. Okay, we don’t always elect great leaders or do the right thing by our neighbours, family, friends. Yet so much has been done. We’re not always rational, no, and neither should we be. Would more people be happier if the balance shifted towards more rationality? Probably. Yet on the whole we go forward, stumbling sometimes, by accident sometimes, yet we do live longer, we have sent people (okay, men) to the moon, vastly fewer children and mothers die in childbirth. It’s not all bad, this world.

Anyway, it’s a good book.


Book book book.


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About Darren

I'm a scientist by training, based in Australia.

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