From Apocalypse Explained ~ Emanuel Swedenborg
... he who loves himself only loves what is his own [proprium], and therefore immerses all things of his will and his understanding in what is his own [proprium], even so that it is impossible for him to be elevated from it to heaven and to the Lord; consequently he sees nothing from the light of heaven, but solely from the light of the world, which light, separated from the light of heaven, is mere darkness in spiritual things, which are the things of heaven and the church; and for this reason also the more a man loves himself the more he despises, yea, denies spiritual things.In consequence also of this the internal spiritual mind, by which man is in the light of heaven, is closed up, and this causes the man to be merely natural, and the merely natural man is inclined to evils of every kind. For the evils into which man is born have their seat in the natural man, and these are removed from him only to the extent in which his interior mind, which receives the light of heaven, is opened; moreover, what is man's own [proprium] has its seat in the natural man, and what is man's own [proprium] is nothing but evil.
(From Apocalypse Explained 653:2)