This episode’s guest, Michael Bond, is the author of The Power of Others, and reading his book I was surprised to learn that despite several decades of research into crowd psychology, the answers to most questions concerning crowds can still be traced back to a book printed in 1895.

Gustave’s Le Bon’s book, The Crowd: A Study of the Popular Mind, explained that humans in large groups are dangerous, that people spontaneously de-evolve into subhuman beasts who are easily swayed and prone to violence. That viewpoint has informed the policies and tactics of governments and police forces for more than a century, and like many prescientific musings, much of it is wrong.

Common sense used to dictate that men and women should only come together for breakfast and dinner.

According to Victorian historian Kaythrn Hughes, people in the early 19th Century thought the outside world was dangerous and unclean and morally dubious and thus no place for a virtuous, fragile woman. The home was a paradise, a place for civility, where perfect angelic ladies could, in her words, “counterbalance the moral taint of the public sphere.”

Hypothetical situations involving dragons, robots, spaceships, and vampires have all been used to prove and disprove arguments.

Statements about things that do not exist can still be true, and can be useful thinking tools for exploring philosophical, logical, sociological, and scientific concepts.

The problem is that sometimes those same arguments accidentally require those fictional concepts to be real in order to support their conclusions, and that’s when you commit the existential fallacy.

Here is a logic puzzle created by psychologists Daniel Kahneman and Amos Tversky.

“Linda is single, outspoken, and very bright. She majored in philosophy. As a student, she was deeply concerned with the issue of discrimination and social justice, and also participated in demonstrations. Which of the following is more probable: Linda is a bank teller or Linda is a bank teller AND is active in the feminist movement?”

In studies, when asked this question, more than 80 percent of people chose number two. Most people said it was more probably that Linda is a bank teller AND active in the feminist movement, but that’s wrong. Can you tell why?