Philosophy of physics is the study of the fundamental, philosophical questions underlying modern physics, the study of matter and energy and how they interact. Perhaps the main questions concern the nature of space and time, atoms and atomism, cosmogony, the interpretation of the results of quantum mechanics, the foundations of statistical mechanics, causality, determinism, and the nature of physical laws. Classically, several of these questions were studied as part of metaphysics (for example, those about causality, determinism, and space and time). Today, the philosophy of physics is very close to and the most active subtopic within philosophy of science.

The main article for this category is Philosophy of physics.