Edition · Sunday, 3 May 2026
What happened, the forces beneath it, why it matters — then your turn.
01 · Lesson · why it matters
The Organ We Can't Figure Out
Scientists have studied the appendix for over a century but still can't agree on what it does. This is how research works when you can't run the obvious experiment.
6 min
Read the lesson
02 · Lab · your turn
Inference from Indirect Evidence
When you cannot observe the variable you need directly, you infer from correlates—but changing which correlate you measure shifts what you conclude, even when all correlates are accurate.
Rehearse the decision