Einstein is supposed to have remarked that “education is what remains when one has forgotten everything they learned at school”. - David Franklin

The phrases ‘certainty is an illusion’ and ‘think probabilistically about the world’, both introduced in the first class, are the first two examples of high-level concepts which Dan calls airport ideas.

He asks the 80 students to respond based on their ‘gut feeling’. Again, students are given five options, ranging from ‘less than 1%’ to ‘above 40%’. About half of them believe the true answer is less than 5%, of which plenty go for the ‘less than 1%’ option. Only 1 in 6 get it right, picking the highest option: it turns out that the true figure is 41%. He invites those people – 13 in total – to stand up.

Dan asks the class whether any of them has ever checked the weather on their phone to see if it’s likely to rain while they’re outside. Everyone has. “What do you do if you see there’s a 30% chance of rain?” “Take an umbrella”, several students all say at once.