When the modern perception of reality had thus been reduced to the material and profane level, it also reduced human nature to its physical and psychological aspects, only.
However the soul is not only a psychic entity, but first of all a spiritual one, which is its principal aspect. This is according to the teaching of all world traditions or metaphysical doctrines:
Thus man has (not two but) *three* levels of being:
the physical, the psychic or psychological and the spiritual.
The organ for the spiritual is mentioned in the words of German theologian Meister Eckehart (d.1327):
"There is something in the soul, which is not created and not possible to create (increatum et increabile); if the whole soul were such, it would be not created and not possible to create; and this is the Intellect (intellectus)."
This modernist 'development' therefore stripped man off his divine, sacred potential. It led to a concept of human nature which is "too unstable, changing and turbulent to be able to serve as the principle for something" or anything at all, because it is grounded on the emotional and often irrational levels of being.
This tendency to reduce human nature can even be observed in some overtly exoteric religious circles - influenced by modernism itself, where there may be lipservice to the Divine, but in practice great focus on moral, behavioural or political issues, neglecting the essential demands of the Divine Law, in respect to inner transformation and spiritual striving.