The Problem With Underdeterminism in Philosophy of Science

Professor Thomas Barrett: Is it possible to have multiple theories that describe the universe and make exactly the same predictions, but are in themselves fundamentally different? He says we encounter a very pernicious kind of underdetermination. In general relativity, intuitively, like since signals can't travel faster than the speed of light, you can only know at most everything that goes on in your past light come. So Manchak proves now that there's always more than one model of the universe according to Einstein's theory that's compatible with the data you could have possibly gathered.