Irrational and Happy About It

If we can be fooled so easily, what's the point of reason?

The New York Times Book Review reviewed Daniel Kahneman's "Thinking, Fast and Slow" Sunday. I've mentioned it a couple of times already, but the book, which I just bought for the Kindle, is a warm and deeply informed take on the cleaved and error prone human mind by the Princeton psychologist and Nobel Laureate. The reviewer Jim Holt, however, raises one point that Kahneman doesn't spend much, if any, time discussing. Namely, if our reasoning ability has developed to cope with the world as it is, then the cognitive illusions described by Kahneman are the norm, not a departure from it.

Even if we could rid ourselves of the biases and illusions identified in this book — and Kahneman, citing his own lack of progress in overcoming them, doubts that we can — it is by no means clear that this would make our lives go better. And that raises a fundamental question: What is the point of rationality? We are, after all, Darwinian survivors. Our everyday reasoning abilities have evolved to cope efficiently with a complex and dynamic environment. They are thus likely to be adaptive in this environment, even if they can be tripped up in the psychologist’s somewhat artificial experiments. Where do the norms of rationality come from, if they are not an idealization of the way humans actually reason in their ordinary lives? As a species, we can no more be pervasively biased in our judgments than we can be pervasively ungrammatical in our use of language

The following logical puzzle is frequently cited as an example of biased thinking in reviews of the book: If a bat and ball cost $1.10, and the bat costs one dollar more than the ball, how much does the ball cost? Think for a moment. The irresistible - and wrong - answer is ten cents. A ten cent ball and a bat that costs $1.10 (one dollar more than the ball) totals $1.20. The correct answer is the ball must cost five cents.

For those of you at IdeaFestival 2011, Daniel Simons did a brilliant job of demonstrating in startling detail how even the obvious visual details are missed when our attention is directed elsewhere. The mind goes astray. It wants to fill in the empty cognitive blanks. It longs for meaning. Our wetware is wildly suggestible and magicians, for one, take advantage of this flaw one misdirected gaze at a time.

Would life go better if we were rid of the mind's shortcomings? Like Holt, I don't think the answer is at all clear. In my view, the shortcomings, when they rise to the level of conscious mistakes, are related to the capacity for suspended belief. Giving up to too soon on the logic comes in mighty handy at the movies or when reading a novel, or expands on the possibilities in games like Minecraft and makes coordinated acts possible in government. The last point is a stretch. But in contrast to make believe, belief-made is that sly waive and a nod to circumstance, the vision that makes transcendent acts possible. In complex and dynamic environments, it's our adaptive and idealized better selves.