 From the early days of quantum mechanics, there has been a strain of thought that holds that the proper attitude to take towards quantum mechanics is an instrumentalist or pragmatic one. On such a view, quantum mechanics is a tool for coordinating our experience and for forming expectations about the outcomes of experiments. Variants of this view include some versions of the Copenhagen interpretation. More recently, views of this sort have been advocated by physicists, including QBists, who hold that quantum states represent subjective or epistemic probabilities (see Fuchs et al., 2014). The philosopher Richard Healey defends a related view on which quantum states, though objective, are not to be taken as representational  (see Healey 2012, 2017a, 2020). For more on these approaches, see entry on  Quantum-Bayesian and pragmatist views of quantum theory.