Wait, Probabilities can be Negative A Peek at Quantum Foundations, So ME1

A video for 3Blue1Browns Summer of Math Exposition 1. See how thinking about negative probabilities can lead us to deep ideas in quantum theory. 00:00 Introduction 01:27 Example with negative probability 09:09 The Double Slit 13:01 Closing thoughts Corrections: At 2:04, I messed up the conventional notation for conditional probability. It should read P(1, S), which means The probability of event 1 happening given that S happened. At 5:16, not 0. 12. So the final answer should have been 0. 74 instead of 0. 68. Similarly, at 5:36, the number on the farthest right branch should be 0. 12, not 0. 18. Basically, I accidentally switched the numbers coming out of B when I made the slides. This does not affect the main points of the video.