In philosophy, the philosophy of physics studies the fundamental philosophical questions underlying modern physics, the study of matter and energy and how they interact. The philosophy of physics begins by reflecting on the basic metaphysical and epistemological questions posed by physics: causality, determinism, and the nature of physical law. It then turns to questions raised by important topics in contemporary physics:

• Physical cosmology: space, time, and the origin and ultimate fate of the universe;
• Thermodynamics and statistical mechanics: energy, work, randomness, information;
• Quantum mechanics: the rival interpretations thereof, and its counterintuitive conclusions.