Answer: After the world of Infinity shattered, the correction was made, and as a result, the worlds of ABYA appeared from the broken state. This system was corrected by the Surrounding Light (Ohr Makif), in other words, by the Light that Reforms.
Then the four levels were corrected: from level zero up to the third one, but not the fourth phase, the “stony heart.” It is impossible to correct it, and it did become the reason for the breakage. So what can be done?
In order to fully reveal this phase, we need an additional special system called Adam. This is the forth level of the fourth phase, which will reveal and correct itself. As we build this system, it joins the pure worlds of ABYA. At that point Adam is starting to receive the Light through them. Its breakage divides the worlds into the pure and impure ones.
There are no worlds by themselves. Their two systems exist only in the perception of Adam who exists in between them. In other words, the systems of the worlds are formed between you and the Creator when you want to reach Him. They reflect your defects, your obstacles on the path. The purity and impurity are tied to you and don’t exist in and of themselves.
From the 4th part of the Daily Kabbalah Lesson 6/27/12, “Introduction to The Book of Zohar”