 Another major issue connected to the doctrine of divine ideas, as should also be clear from the previously quoted passage, was the bundle of epistemological questions involved in Augustine’s doctrine of divine illumination. The doctrine — according to which the human soul, especially “one that is holy and pure”, obtains a specific supernatural aid in its acts of understanding, by gaining a direct insight into the Divine Ideas themselves — received philosophical support in terms of a typically Platonic argument in Augustine’s De Libero  Arbitrio.[18]  The argument can be reconstructed as follows.