Question 75. Man who is composed of a spiritual and a corporeal substance: and in the first place, concerning what belongs to the essence of the soul
"It is because the contemporary alternatives seem so one-sided and are not more evidently solutions to the problems which Thomas faced, and partly solved, that we return to him and to the tradition of theology and philosophy in which his Summa Theologiae appears: theology as the science of the first principle and this as the total knowledge of reality in its unity." -- Wayne J. Hankey, God in Himself (Oxford University Press, 1987), p.159.
Question 75. Man who is composed of a spiritual and a corporeal substance: and in the first place, concerning what belongs to the essence of the soul