 The main focus of the Second Book of the Periphyseon is an analysis of what Eriugena terms “the Primary Causes” (causae primordiales) which are the patterns of all things located in the mind of God and function as the timeless and unchanging causes of all created things. This doctrine represents an eclectic combination of various earlier doctrines, including the Platonic theory of Forms or ideai, Dionysius’ discussion of the divine names, and Augustine’s revival of the Stoic notion of eternal reasons (rationes aeternae).