ABSTRACT. Barrett writes that quantum mechanics and special relativity are the two cornerstones of modern physics. Balaguer contends that propensities are just physical properties, like temperatures and lengths, and so we can get rid of them. Lewis argues that on a realist construal of quantum mechanics, the quantum state determines the truth-values of claims about macroscopic objects. Arntzenius holds that in quantum particle mechanics there are additional reasons to reject states that correspond to point values for continuous observables, including positions.