Thursday December 12, 2019

Guide to critical thinking is a handy handbook

Sociology

24th November, 2019
2

By David Robert Grimes

Simon & Schuster, €17.95

In 1958, China launched the Great Sparrow Campaign. Believing that sparrows ate the grain planted by farmers, the Chinese government denounced the birds as “the public animals of capitalism” and ordered their extermination. They were shot, their nests destroyed and their eggs broken. Within a year, about a billion sparrows were dead.

But autopsies revealed that sparrows didn’t just eat grain. Their main food source was insects. With no sparrows, insect populations ballooned and locusts destroyed crops. Together with other catastrophic policies, the disastrous Great Sparrow Campaign contributed towards the Great Chinese Famine, in which up to 45 million people died.

As David Robert Grimes’s The Irrational Ape frequently demonstrates, faulty reasoning can have devastating consequences. In a post-truth world of populists and fake news, this book styles itself as a timely guide to critical thinking. It has two main strands: outlining the most common flaws in our logic, and counselling us on how to avoid these traps.

Grimes is a cancer researcher, physicist, and science writer. A hallmark of the Dubliner’s book is the breadth of its canvas: the evidence Grimes uses to illustrate his contentions is as likely to come from history and politics as from science and health.

In September 1983, when the Cold War was at its height, the USSR’s early warning system signalled five US missiles approaching the country. It seemed that nuclear war had begun. The duty of Stanislav Petrov, a lieutenant colonel in the Soviet Air Defence Forces, was to inform his superiors so that Moscow could, in response, launch their nuclear warheads.

Petrov phoned his superiors, but told them that the warning system was faulty. He calmly reasoned that if the US attacked, it would be full-scale rather than five missiles. Petrov’s critical analysis – ultimately preventing nuclear annihilation – was vindicated: the warheads that had been "detected" by the warning system were reflections from low clouds.

In contrast, our belief that vitamin C is a remedy for a cold is an enduring myth. Linus Pauling, a winner of the Nobel Prize for Chemistry, made the claim in a bestselling 1970 book that sent demand for vitamin C skyrocketing. There were no scientific grounds for Pauling’s thesis, but the myth took root because of his perceived authority.

This episode is an example of a reasoning error where the support of an authority (Pauling’s renown in chemistry) is used to justify a conclusion (vitamin C’s benefits) and it’s typical of the errors that Grimes delineates. He assembles the errors into three broad categories: logical, rhetorical, and psychological. We’re familiar with errors like cherry-picking, but others, such as apophenia (the tendency to mistakenly perceive patterns in random data), are more obscure.

Grimes’s prescription for avoiding thinking errors is reassuringly straightforward. When we’re presented with any argument, he recommends adopting scientific scepticism and analytical thinking. This means, for example, questioning the credibility of the sources, tracing the flow of logic through the argument, and examining whether the premises lead to the conclusion that is claimed.

The main thrust of the book is defining and explaining more than 40 different thinking errors. The Irrational Ape is not in the format of a handbook but, given its focus, it can read like one. It is probably best appreciated as a companion, packed with case studies, to disentangling critical mistakes – a text to dip in and out of – rather than read sequentially.

At a time when we have never been exposed to so much information and disinformation, The Irrational Ape provides a mostly clear-sighted reference for recognising flaws both in our own logic and in the logic of those who seek to influence us.

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