Fusis, Phusis or Physis (; Ancient Greek: φύσις [pʰýsis]) is a Greek philosophical, theological, and scientific term, usually translated into English—according to its Latin translation "natura"—as "nature". The term originated in ancient Greek philosophy, and was later used in Christian theology and Western philosophy. In pre-Socratic usage, physis was contrasted with νόμος, nomos, "law, human convention". Another opposition, particularly well-known from the works of Aristotle, is that of physis and techne – in this case, what is produced and what is artificial are distinguished from beings that arise spontaneously from their own essence, as do agents such as humans. Further, since Aristotle the physical (the subject matter of physics, properly τὰ φυσικά "natural things") has been juxtaposed to the metaphysical.