A puzzle
You have a magic box with two buttons on it labeled C and D. The box is filled with an unknown number of particles flying around at random. When you push button C, a single new particle magically appears inside the box; when you push D, a single particle magically vanishes from the box.
I say there’s a subtle breakage of symmetry in how these two buttons operate. Can you spot it?
Note: it’s deeper than the fact that the two buttons are “opposite” in the sense of one creating and the other destroying a particle.
