Sunday, September 23, 2018

How Not to Be Wrong by Jordan Ellenberg


When people complain about math being too hard or impractical, one might expect a college math professor to take up a defense, which Jordan Ellenberg does in How Not to Be Wrong. He manages to make is his argument without resorting to equations, and with very few numbers.

Math is not all about equations and numbers (though these are important objects in math). Ordinary people do math frequently in the form of thinking with a little more depth, rigor and structure than usual. This is the power of math to help us make better decisions. Though Ellenberg covers a lot of ground in math, science and history, the notion of better decision making through math runs through each chapter.

Along the way, he debunks some common uses of math, even those that are prevalently used among math-minded scientists. For instance, he takes on the notion of statistical significance, which sometimes bothers me, too. Statistical significance by itself is not an arbiter of the truth of something. It has a lot more to do with a particular way of framing arguments and the sensitivity of an experiment. If you have a large enough sample, you’re likely to have statistically significant results, even if those results are insignificantly small. You can “prove” ridiculous, plainly wrong things using an argument from statistical significance because improbable things happen sometimes (actually a lot).

Ellenberg discusses the related subject of probability, which any book like this should. Human beings are pretty bad at grasping probability; it requires deeper, rigorous, structured thinking that sometimes runs counter to our intuition.

Though math is sometimes misused or misunderstood, Ellenberg is bullish on the power of math to help us make better decisions and understand the world more deeply. Math itself is a pretty deep world, and mathematicians have discovered connections between things that seem to be unrelated. That is part of the power of math. Solutions in one are often lead to applications in many others.

Of course, math won’t eliminate uncertainty, though it can help you understand uncertainties better. I’ve spent most of my career in and around government and Ellenberg expresses some empathy for decision makers in the realm of policy, writing, “Maker of public policy do not have the luxury of uncertainty that scientist do. They have to for their best guesses and make decisions on the basis thereof.” This guesswork can be done with humility and honesty, as is fitting in a republic.

While Ellenberg eschews the pile of symbols many people think of as math, he does not avoid deep, challenging questions. It’s not the math you’ll find in journals, but it’s not fluff. He doesn’t call people to join the ranks of academic mathematicians (though don’t give up on the idea just because it seems hard at first), but he argues that people in all manner of professions could benefit from education in math. If you’re interested in becoming such person, How Not to Be Wrong is a good introduction to how mathematicians think about the world.

If you’re interested in this book, you may also be interested in

Ellenberg, Jordan. How Not to Be Wrong: The Power of Mathematical Thinking. New York: Penguin, 2014.

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