Nov 20, 2019
[Followup to: Building Intuitions On Non-Empirical Arguments In Science]
In your travels, you arrive at a distant land. The chemists there believe that when you mix an acid and a base, you get salt and water, and a star beyond the cosmological event horizon goes supernova. This is taught to every schoolchild as an important chemical fact.
You approach their chemists and protest: why include the part about the star going supernova? Why not just say an acid and a base make salt and water? The chemists find your question annoying: your new “supernova-less” chemistry makes exactly the same predictions as the standard model! You’re just splitting hairs! Angels dancing on pins! Stop wasting their time!
“But the part about supernovas doesn’t constrain expectation!” Yes, say the chemists, but removing it doesn’t constrain expectation either. You’re just spouting random armchair speculation that can never be proven one way or the other. What part of “stop wasting our time” did you not understand?
Moral of the story: It’s too glib to say “There is no difference between theories that produce identical predictions”. You actually care a lot about which of two theories that produce identical predictions is considered true.