Philosophy of physics is the philosophical and conceptual study of the major physical theories: statistical mechanics, quantum mechanics and quantum field theory, and theories of space-time, gravity, and cosmology. It is also concerned with the nature of symmetries and symmetry breaking, probability theory, and historically important theories, such as Newtonian gravity.

It overlaps with a number of major topics in philosophy of science – the nature of laws, scientific explanation, theory change, and theory formulations – but it is in general pursued with a greater engagement with the content of physical theories (hence metaphysics), rather than general questions in scientific method and theory of knowledge (epistemology).

Philosophy of Physics - Oxford University