Arnobius — Against the Nations 2.31
31.1. A certain mid-state, then, and the doubtful and ambiguous nature of souls, gave birth to a place for philosophy and found a cause why it should be sought, while of course that one fears danger from evils admitted, the other conceives good hopes if he does nothing of crime and leads life with duty and justice.
2. From this it is that among learned men and those gifted with excellence of talents there is a contest about the quality of souls, and some say they are of mortal nature and cannot sustain a divine substance, but others that they are perpetual and cannot degenerate into mortal nature, because that this happens is effected by the law of mid-state: for both those have arguments ready by which they are found passible and perishable, and these in turn do not lack arguments by which they are shown to be divine and immortal.
Latin
31.1. Medietas ergo quaedam et animarum anceps ambigua que natura locum philosophiae peperit et causam cur appeteretur invenit, dum periculum scilicet ex malis iste formidat admissis, alter concipit spes bonas, si nihil sceleris faciat et cum officio vitam iustitiaque traducat.
2. Inde est quod inter doctos viros et ingeniorum excellentia praeditos de animarum qualitate certamen est et eas alii dicunt mortali esse natura nec divinam posse substantiam sustinere, alii vero perpetuas nec in naturam posse degenerare mortalem, quod istud ut fiat, medietatis efficitur lege: quod et illis argumenta sunt praesto, quibus eas passivas atque interibiles invenitur, et his contra non desunt quibus esse divinas immortalesque monstratur.