" At its most simple, the notion underlying The Great Chain of Being, as identified in the first instance by Plato, is that the universe is essentially a rational place, in which all organisms are linked in a great chain, not on one scale of low to high (for Plato could see that even ‘lowly’ creatures were perfectly ‘adapted’, as we would say, to their niches in the scheme of things) but that there was in general terms a hierarchy which ranged from nothingness through the inanimate world, into the realm of plants, on up through animals and then humans, and above that through angels and other ‘immaterial and intellectual’ entities, reaching at the top a superior or supreme being, a terminus or Absolute. "

― Peter Watson , Ideas: A History of Thought and Invention, from Fire to Freud