He is introduced by Cicero as an interlocutor in the De oratore and De natura deorum (iii.), as a supporter of the principles of the New Academy.
A special interest attaches to the dialogues written after the manner of Plato but with Aristotle as principal interlocutor; and some of these, e.g.
In the first of his Dialogues (fair models of Cicero), Severus puts into the mouth of an interlocutor (Posthumianus) a pleasing description of the life of coenobites and solitaries in the deserts bordering on Egypt.
The judgment of Severus himself is no doubt that which he puts in the mouth of his interlocutor Posthumianus: "I am astonished that one and the same man could have so far differed from himself that in the approved portion of his works he has no equal since the apostles, while in that portion for which he is justly blamed it is proved that no man has committed more unseemly errors."
In 633 he was one of the party of Sophronius of Jerusalem (the chief original opponent of the Monothelites) at the council of Alexandria; and in 645 he was again in Africa, when he held in presence of the governor and a number of bishops the disputation with Pyrrhus, the deposed and banished patriarch of Constantinople, which resulted in the (temporary) conversion of his interlocutor to the Dyothelite view.