Therefore, Atik is the “indirect source” of Atzilus and that other worlds, and serves as the intermediary between the Infinite Light of Hashem and the beginning of worlds, starting with Arich and Atzilus.
Since the existence of Chochma-Wisdom, as derived from Keser-Crown comes from literally ‘ayin-nothing in the same category at all.’ (ex-nihilo). It does not come to be by way of orderly progression from one level to another, similar, but lower level.
In other words, for Chochma to come into being from Kesser, especially from Atik, there needs to be a “jump,” from Infinite to finite. This is unlike the progression from Chochma to Bina, and from Bina to Ze’eir Anpin etc., since those levels are all in the same general category, similar to the orderly fashion of cause and effect, e.g., intellect producing emotions.
Now, in each of the four Worlds of Atzilus, Beriya, Yetzira and Asiya, there is a level of Keser that serves as an intermediary level:
Malchus of Atzilus becomes Keser of Beriya, and Malchus of Beriya becomes Keser of Yetzira. The level of Malchus of each level becomes the intermediary level for the next world to come into being. This is because Malchus has two level: It has one aspect of how it exists in its own world, and one aspect of how it “descends” into the next, lower, world. Because of this, it can be the “connection point” between the worlds. From the perspective of the lower world, the Malchus of the higher world is called Kesser, and from the perspective of the higher world it is called Kesser. (This is similar to a building with many levels: The floor of one level is also the ceiling of the lower level.)
However, the difference between the Keser of Atzilus connecting it to the Infinite Light to the Keser in between each world is as follows:
The existence of Atzilus is by way of a Tzimtzum-contraction/withdrawal of Hashem’s Infinite Light. This causes an “empty space” and a “void” in which Hashem’s revelation is withheld.
However, the existence of Beriya, Yetzira and Asiya comes by means of a “Parsa-Curtain,” which separates between Atzilus and Beriya, and then between Beriya and Yetzira, etc. However, the three lower worlds do not come to be through an “empty space.”
Now, the difference between a “Parsa-Curtain” and a “Mokom Ponui-An Empty Space,” can be understood by first explaining the idea of a “Tzimtzum- Withdrawal” of Hashem’s Infinite Light.
