Here is a photo of a picture that hangs on the wall of a friend’s home. Karl Popper dons sunglasses. Hanging from his mouth is a broken rose of socialism, the color of congealed blood.

Logik der Forschung is German for logic of research.


Four cards are shown, each card showing a character on the side shown, namely A, B, 2, and 3, respectively.


Consider the following proposition:

Proposition P: If one side of a card has a vowel, then on the other it has an even number.

To establish that none of these four cards falsifies Proposition P, which cards must one turn over?

When my friend put the question to his besotted dinner group, we puzzled over it merrily. Feel free to answer in the comment field. This exercise in falsificationism might help us discover the value and complications of falsification as scientific practice. If reader response seems to justify it, I will follow up.