What is essential in the machine is only the interaction of its parts. The unifying principle that governs that interaction does not exist in the object itself but outside it as a plan in the head of its builder. Only the most extreme shortsightedness can deny that the difference between an organism and a mechanism is precisely the fact that in a machine the determining principle governing the interrelationship of its parts is external (and abstract), whereas in an organism it assumes a real existence in the object itself. 

R. Steiner