 There are also arguments that focus, at least implicitly, on chemistry’s ontology. A well-known strand of contemporary metaphysics defends physicalism, the doctrine that everything in the universe is physical (see the entry on  physicalism).  According to the physicalist, chemistry is “nothing but” physics, even though chemical explanations and theories are not derivable from physics. The physical world is simply composed of the fundamental particles of physics. Chemical entities and their properties have no independent reality.