To argue for God's goodness and omnipotence, Augustine traced the origin of evil back to human anima, dividing this anima into the higher part that includes intellectus, voluntas and memoria, as well as the lower part that cannot govern or disturb the higher part. Augustine eventually postulated voluntas, the driving force of anima, to be the author of evil. By elevating voluntas as a philosophical concept, Augustine avoided any possible threats that Greco-Roman philosophy could pose to the Christian theory of creation and also gave rise to the convincing origin of moral evil.