31 A certain neutral character, then, and undecided and doubtful nature of the soul, has made room for philosophy, and found out a reason for its being sought after: while, that is, that fellow is full of dread because of evil deeds of which he is guilty; another conceives great hopes if he shall do no evil, and pass his life in obedience to duty and justice. Thence it is that among learned men, and men endowed with excellent abilities, there is strife as to the nature of the soul, and some say that it is subject to death, and cannot take upon itself the divine substance; while others maintain that it is immortal, and cannot sink under the power of death. But this is brought about by the law of the soul's neutral character: because, on the one hand, arguments present themselves to the one party by which it is found that the soul is capable of suffering, and perishable; and, on the other hand, are not wanting to their opponents, by which it is shown that the soul is divine and immortal.
Source: Against the Heathen (New Advent)