The Abyss is the great gulf or void between the phenomenal world of manifestation and its noumenal source.
This doctrine is extremely difficult to explain; but it corresponds more or less to the gap in thought between the Real, which is ideal, and the Unreal, which is actual. In the Abyss all things exist, indeed, at least in posse, but are without any possible meaning; for they lack the substratum of spiritual Reality. They are appearances without Law. They are thus Insane Delusions.
Now the Abyss being thus the great storehouse of Phenomena, it is the source of all impressions.