2. Schrödinger’s cat
A cat is trapped in a box with radioactive material, a Geiger counter, and a mechanism rigged to release poison if particle decay is detected. According to Erwin Schrödinger, the cat exists in two probable states. But that doesn’t track with reality (cats are not both alive and dead). Proposed in 1935, the postulate illustrates that some quantum concepts just don’t work at nonquantum scales. Also that Schrödinger was a dog person.
8. Parfit’s teleporter
Philosopher Derek Parfit is famous for basing thought experiments on sci-fi. In 1984, he envisioned a teleporter malfunction, like the one that made two James T. Kirks in an episode of Star Trek. Teleporters annihilate every particle in you, then rebuild them from scratch. What happens if the original isn’t destroyed? Which is the real you? Parfit says both. Evil Kirk would disagree.