Rationality is like a muscle that needs constant flexing

In the 1964 film My Fair Lady after Colonel Pickering has secured the help of an old friend to pull strings at the Home Office (plus ça change) in the hope of finding the absconded Eliza Doolittle, Professor Higgins snaps:

Why is thinking something women never do? And why is logic never even tried? Straightening up their hair is all they ever do. Why don’t they straighten up the mess that’s inside?

Today the sex and gender wars are more nuanced than that, at least in public, but the charge of stupidity and unthinkingness has found many other targets: anti-vaxxers, Brexiteers, conspiracy theorists, climate- change activists on the M25, Republicans, Democrats and the Prime Minister (if only he’d straighten up his hair).

Unlike Henry Higgins’s pointed criticism, Steven Pinker, a Harvard professor of cognitive psychology and seasoned populariser of subjects far beyond, sees a mess inside every one of us. He takes an evolutionary perspective to argue that the mess is getting worse; humans aren’t used to the volume, immediacy and pace of information that fuels our connected lives. In essence, we fail woefully to be rational. But do we really want to fare better? Rational personalities can seem dull and inhibited. And there’s entertainment to be had in spurning the fact-checkers and half believing the outrageous stories that reach our Twitter feeds.

Pinker aims to make cognitive exercise as aspirational and appealing as working on your six-pack

What is rationality? Pinker settles on the definition that it’s ‘the ability to use knowledge to attain goals’, or to work with the truth to get where we want. The opposite of rationality is harder to define. It’s not strictly unreasonableness, or illogic, or emotionality, as all of these can be rational (Pinker does a good job in explaining how). Rationality cannot tell us what to value, at least not directly.