Pius XII is clearly committed to some form of dualism. The emphasis is on human nature as more than simply the material from which it emerged in the evolutionary process. Mental activities, then, are emergent properties which cannot be reduced entirely to the next lower level of reality. This is not substance dualism or for that matter any form of dualism. There is no soul in the sense of a substance distinct from the body.
Human beings are a unity, but they are more than a sum of their physical constituents.
Mind or soul is a higher level of organization in a universe of multiple levels. As an afterword, Dr. Murphy briefly addressed the issue of life after death. Most Medieval philosophers and theologians were dualists, probably because two of the most influential of the early Fathers of the Church, Origen and Augustine, were dualists. The Christian tradition evolved into a combination of Greek immortality with Semitic resurrection. The soul at death enters an intermediate state and the self is not completed until the final resurrection.