How Quantum Theory Helps Us Explain

I offer an account of how the quantum theory we have helps us explain so much. The account depends on a pragmatist interpretation of the theory: this takes a quantum state to serve as a source of sound advice to physically situated agents on the content and appropriate degree of belief about matters concerning which they are currently inevitably ignorant. The general account of how to use quantum states and probabilities to explain otherwise puzzling regularities is then illustrated by showing how we can explain single-particle interference phenomena, the stability of matter, and interference of Bose–Einstein condensates. Finally, I note some open problems and relate this account to alternative approaches to explanation that emphasize the importance of causation, of unification, and of structure. 1 Introduction 2 Two Requirements on Explanations in Physics 3 What We Can use Quantum Theory to Explain 4 The Function of Quantum States and Born Probabilities 5 How These Functions Contribute to the Explanatory Task 6 Example One: Single-Particle Interference 7 Example Two: Explanation of the Stability of Matter 8 Example Three: Bose Condensation 9 Conclusion 1 Introduction 2 Two Requirements on Explanations in Physics 3 What We Can use Quantum Theory to Explain 4 The Function of Quantum States and Born Probabilities 5 How These Functions Contribute to the Explanatory Task 6 Example One: Single-Particle Interference 7 Example Two: Explanation of the Stability of Matter 8 Example Three: Bose Condensation 9 Conclusion