Thesis Many-worlds is the most conservative reading of quantum mechanics, not the wildest

Many-worlds has a reputation as the science-fiction interpretation. I want to argue it is the opposite: the reading that adds least to the physics.

Look at what the others add. Copenhagen-style views add a collapse whenever a "measurement" happens, without saying what counts as one. Objective-collapse theories add new dynamics that the standard equations do not contain. Pilot-wave adds particles with definite positions on top of the wave, plus a guidance law. QBism reinterprets the wavefunction as belief, which changes what the theory is about.

Everett's 1957 proposal adds nothing. Take the Schrödinger equation, the one part of the theory everyone agrees on, and let it run, including on measuring devices and on us. What you get is a wavefunction that develops into many nearly independent branches, and decoherence explains why each branch looks classical from the inside. The "worlds" are not an extra postulate; they are what the equation already describes once you stop interrupting it.

Yes, the result has an enormous number of branches. But parsimony in science has usually meant fewer laws and fewer kinds of thing, not fewer instances. Nobody rejected astronomy because it multiplied galaxies.

I write software for a living, and I like theories whose code is short. Persuade me the code isn't short, or that short code is the wrong criterion.