Extraordinary Popular Delusions and the Madness of Crowds: 8 key ideas
The core ideas of Extraordinary Popular Delusions and the Madness of Crowds, each in under a minute, written in our own words. Want the full depth? Get the book.
- IDEA 1 OF 8
Whole crowds can lose their judgement
Mackay collects stories of times when large numbers of people believed in something foolish all at once.
He argues that people think in herds, and often recover their good sense slowly, one person at a time.
- IDEA 2 OF 8
John Law's scheme gripped France
Mackay tells how John Law's Mississippi Company in France sold shares that rose wildly on promises of riches from America.
When confidence collapsed, many people who had borrowed and bought at high prices were ruined.
- IDEA 3 OF 8
The South Sea Bubble burst
Mackay describes how shares in England's South Sea Company soared as politicians and ordinary investors rushed in.
Dozens of doubtful companies appeared to catch the excitement, and the crash that followed caused great hardship.
- IDEA 4 OF 8
Tulips once cost a fortune
Mackay tells how, in the seventeenth century Netherlands, rare tulip bulbs became objects of fierce speculation.
Prices rose far beyond any use for the flowers, then fell suddenly, leaving many traders with heavy losses.
- IDEA 5 OF 8
Alchemy promised gold from nothing
Mackay describes centuries of alchemists who claimed they could turn ordinary metals into gold or find a potion for eternal life.
He shows how hope and greed kept rulers and followers funding them despite repeated failure.
- IDEA 6 OF 8
Fear fuelled the witch hunts
Mackay describes the European witch mania, when panic and accusation led to the deaths of many innocent people.
He presents it as a terrible example of how fear can spread through a whole society.
- IDEA 7 OF 8
Faith and excitement drove the Crusades
Mackay presents the Crusades as partly a mass enthusiasm, in which religious feeling and excitement swept huge numbers of people into long, deadly campaigns.
He stresses how quickly such moods can spread.
- IDEA 8 OF 8
Healers and prophets drew crowds
Mackay also describes fortune tellers, prophets of doom and magnetisers who claimed strange healing powers.
He uses them to show how readily people accept confident claims when they badly want to believe.
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