Mathematics
Bayesian vs. Frequentist Interpretations of Probability
Quick fact
The frequentist definition of probability was formalized by Richard von Mises in the early 20th century, but the Bayesian approach actually came first: Bayes' theorem was published in 1763.
Why this is interesting
If a meteorologist says there’s a 70% chance of rain tomorrow, do they mean it will rain 7 out of every 10 days like this? Or are they 70% confident it will rain?