 It is to be noted, however, that all these things do not always require articulation, for often, the usefulness becomes clear at the same time as the goal, while the title is obvious to everyone, as [in the case of] the On the Soul. Authenticity, for its part, does not need to be established in every case, but in general only when there is some starting-point for controversy. (Simplicius, In Cat. 8.31–9.3, translated by M. Chase)