Philosophy of physics

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, 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.
Centuries ago, the study of causality, and of the fundamental nature of space, time, matter, and the universe were part of metaphysics. Today the philosophy of physics is essentially a part of the philosophy of science.