Saint Augustinus subjects to a meticulous surveying the imaginative event in its complexity, like a total psycho-physic process (and therefore its somatic implications). Its specific products –the fantastic creations– are some peculiar expressive and interpretative modalities of the truth. They are produced spontaneously in the course of the cognitive activity and that they have however need of a continuous correction. For this reason, their relationship to the truth do not correspond immediately. A relevant moment is the Augustinus’ critical considerations of “Manichaean materialism” by using some ideas from Neoplatonism.