How we meet the future

It seems an obvious, if understandable, mistake to generalise beyond what our evidence supports. A child playing in the park may assume, based on their experiences of their friendly pet golden retriever, that all dogs are friendly. But they would be wrong to approach an XL Bully, a breed of dog effectively outlawed in the UK recently following a string of attacks on children.

When someone makes unwarranted generalisations about social groups, we condemn them for the sin of stereotyping. It is wrong to conclude after just one experience with a rude Brit that all Brits are rude. We hear less about the problems of undergeneralising.

Generalising comes so naturally that few of us are at any risk of undergeneralising, so we give it little thought. The focus on overgeneralising is understandable given its potential costs, such as the child assuming that a dangerous dog is just like the friendly dogs they’ve encountered to date. Generalising itself, though, isn’t a bias that needs to be corrected.

It is a cognitive shortcut and a fundamental part of our mental life. It gives our experience structure and frees us up to focus on the new at the expense of the old. The child who approaches the XL Bully and the person who stereotypes Brits risk making a mistake, but the source of their error is not their desire to generalise.

What, then, is wrong with overgeneralising? Our story begins in Cambridge, 1930. Searching through the papers of his recently deceased friend, the philosopher Richard Braithwaite discovered a sheaf of handwritten notes on the nature of general beliefs, such as the belief that all humans are mortal.

The friend was Frank Plumpton Ramsey, the remarkable philosopher and mathematician described as a ‘genius by all tests for genius’ by Paul Samuelson, the Nobel Laureate in economics. The notes were written in September 1929, just four months before Ramsey’s death from a mysterious illness that he may have contracted from swimming in the River Cam. Ramsey died aged just 26 but would go on to leave an oversized legacy in philosophy, mathematics, economics and logic.