> "they'd be unable to explain ... GPS, because it requires an understanding of general relativity to work.
It requires GR to make it work, but not GR to understand how it works. I.e., GPS would work fine -- in fact, be easier -- in a world without GR. The clocks on board the satellites depend on QM, but the idea of an accurate clock is easy. Same with orbits -- staged rockets came late, but orbital mechanics goes back a long way. Transistors are new, but amplification is old.
It requires GR to make it work, but not GR to understand how it works. I.e., GPS would work fine -- in fact, be easier -- in a world without GR. The clocks on board the satellites depend on QM, but the idea of an accurate clock is easy. Same with orbits -- staged rockets came late, but orbital mechanics goes back a long way. Transistors are new, but amplification is old.