Time’s arrow and reality’s randomness succumb to quantum thermodynamics
Randomness and reality go together like pizza and beer. March and madness. Ice and cream.
It didn’t used to be that way. Isaac Newton supposedly established that reality wasn’t random at all. It was “deterministic” — as regular as clockwork. Tock always followed tick. If you knew where everything was and how it was moving, you could figure out what everything would be doing at any time in the future.
But in the 19th century, determinism’s grip on the scientific view of reality began to slip. Maxwell, Boltzmann and other physicists pointed out that you couldn’t really know every molecule’s location and speed. You had to assume that the molecules bumped into each other at random, then calculate the likely outcome of all their collisions. Enshrined as the second law of thermodynamics, that approach allowed precise predictions of the behavior of gases and other physical systems. And it explained why time flowed in only one direction. Entropy, the measure of how messed up a system is, always increases until equilibrium is reached — thanks to the way randomness produces highly probable arrangements of things. (Messy, of course, is always much more probable than neat.)