Driving knowledge work in the ’30s was the fact that more young people stayed in school because they had nothing else to do. High school graduation surged during the Depression to levels not seen again until the 1960s.

What do I desperately want to be true so much that I think it’s true when it’s clearly not?

Electricity becoming a “willing servant”—introducing washing machines, vacuum cleaners, and refrigerators—freed up hours of household labor in a way that let female workforce participation rise.

The first supermarket opened in 1930. The traditional way of purchasing food was to walk from your butcher, who served you from behind a counter, to the bakery, who served you from behind a counter, to a produce stand, who took your order. Combining everything under one roof and making customers pick it from the shelves themselves was a way to make

What’s different now is the size of the global economy, which increases the sample size of potential crazy things that might happen. When eight billion people interact, the odds of a fraudster, a genius, a terrorist, an idiot, a savant, a jerk, or a visionary moving the needle in a significant way on any given day is nearly guaranteed.

“The course of evolution has been to reduce the number of parts and to adapt those which remain more closely with their special uses, either by increase in size or by modifications of their shape and structure,” Williston wrote in 1914. Animals with hundreds of teeth often evolved to have a handful of specialized incisors, canines, and molars.

They all either came directly from, or were heavily influenced by, the military. Why? Are militaries home to the greatest technical visionaries? The most talented engineers? Perhaps. But more importantly, they’re home to Really Big Problems That Need to Be Solved Right Now.

Spending on road construction went from 2 percent of GDP in 1920 to over 6 percent in 1933 (versus less than 1 percent today). The Department of Highway Transportation tells a story of how quickly projects began: Construction began on August 5, 1933, in Utah on the first highway project under the act. By August 1934, 16,330 miles of new roadway

The next is accepting that what’s rational to one person can be crazy to another. Everything would compute if everyone had the same time horizon, goals, ambitions, and risk tolerances. But they don’t.