Information travels so quickly, and is so freely circulated in the internet age that I don’t pretend that the following story is reaching anyone for the first time. What was once an amazing example of non-obvious critical reasoning taught in universities, these days may be familiar to students before they reach high school. This example even has a Wikipedia page, entitled the Birthday Paradox. Still, for context, I’ll relay how I first learned of this probability question and why it applies to baseball.