Nicholas Murray Butler on Optimism

How (not) to end up in the ash heap of history.

There are limits to where physics makes meaningful predictions: beyond the Planck length, time, or energy. Here’s why we can’t go further.

“For every PhD there is an equal and opposite PhD.”

“It’s a true fact, but a bizarre one, that the reason why hundreds of thousands of people died in Hiroshima and Nagasaki rather than Kyoto and Kokura, is because of a 19-year-old vacation and a passing cloud.”

All stars shine due to an internal source of energy. Usually, it’s nuclear fusion: converting mass into energy. What makes them most bright?