"One central question in the philosophy of physics is how we should understand quantum mechanics (QM). We may want to know what we should take QM to be about. It’s worth noting that, in some (but not all) cases, this is no longer an empirical question: for instance, the traditional Copenhagen interpretation of QM is empirically equivalent to the Everett "many worlds" interpretation of QM. So, if we can’t do an experiment to settle the issue, we need to resort to some other method, which is where philosophers of physics come in."