psychology is necessarily depth psychology, since, as we have seen above, soul refers to the inner, the deep. And the logic of psychology is necessarily the method of understanding which tells of the soul and speaks to the soul in its own language.
Hillman argues that depth psychology is not one option among many but the only form of psychology adequate to its object, the soul, whose intrinsic interiority demands methods commensurate with depth.
, Suicide and the Soul, 1964thesis