Comment by belter

Popper’s rule is not falsifiable for the same reason a definition can’t define itself. Falsifiability judges claims, not the rules for judging claims. Mixing those levels is like asking whether the rules of chess can checkmate themselves.

In category theory terms, it’s a type error, applying a rule defined within a system to the meta-level that defines the system itself.

https://www.lesswrong.com/w/object-level-and-meta-level

https://en.wikipedia.org/wiki/Metatheory