One who heuristically solves or defines problems in reality and asks about the thought and material used in its scientific principle to come up with a theory.
The Metaphysician describes a piece of wood by its chemical properties and tries to watch it burn in a fire. They wonder about how it burns and what a flame is and how that is made. The idea is physics, how does it work. In variant they look at anything that has not been proven in the unknown. "Prote, hyle,?" They say.