Sabine Hossenfelder in Nautilus:
Quantum mechanics is more than a century old, but physicists still fight over what it means. Most of the hand wringing and knuckle cracking in their debates goes back to an assumption known as “realism.” This is the idea that science describes something—which we call “reality”—external to us, and to science. It’s a mode of thinking that comes to us naturally. It agrees well with our experience that the universe doesn’t seem to care what theories we have about it. Scientific history also shows that as empirical knowledge increases, we tend to converge on a shared explanation. This certainly suggests that science is somehow closing in on “the truth” about “how things really are.”
Alas, realism is ultimately a philosophical position that itself has no empirical basis. All we can tell for sure is whether a certain hypothesis is any good at describing what we observe. Yet whether that description is about something that is independent and external to us, the observer, is a question we cannot ourselves ever answer.
This, needless to say, is not a new conundrum, but one that philosophers have discussed for as long as there’ve been philosophers. But it is alive and kicking in the debate about interpretations of quantum mechanics today, as Jim Baggott reminds us in his new book Quantum Reality: The Quest for the Real Meaning of Quantum Mechanics. If this is the age of quantum reason, then Baggott is its Voltaire.