“Enq: But how does your theory avoid this? How can you reconcile the theory of Soul’s omniscience with its blindness to that which is taking place on earth?
Theo: Because such is the law of love and mercy. During every Devachanic period the Ego, omniscient as it is per se, clothes itself, so to say, with the reflection of the “personality” that was.
I have just told you that the ideal efflorescence of all the abstract, therefore undying and eternal qualities or attributes, such as love and mercy, the love of the good, and true and the beautiful, that ever spoke in the heart of the living “personality”, clung after death to the Ego, and therefore followed it to Devachan.
For the time being, then, the Ego becomes the ideal reflection of the human being it was when last on earth, and that is not omniscient. Were it that, it would never be in the state we call Devachan at all.
Enq: What are your reasons for it?
Theo: If you want an answer on the strict lines of our philosophy, then I will say that it is because everything is illusion (Maya) outside of eternal truth, which has neither form, colour, nor limitation.
He who has placed himself beyond the veil of maya – and such are the highest Adepts and Initiates – can have no Devachan. As to the ordinary mortal, his bliss in it is complete.
It is an absolute oblivion of all that gave it pain or sorrow in the past incarnation, and even oblivion of the fact that such things as pain or sorrow exist at all.
The Devachanee lives its intermediate cycle between two incarnations surrounded by everything it has aspired to in vain, and in the companionship of everyone it loved on earth.
It has reached the fulfillment of all its soul-yearnings. And thus it lives throughout long centuries an existence of unalloyed happiness, which is the reward for its sufferings in earth life.
In short, it bathes in a sea of uninterrupted felicity spanned only by events of still greater felicity in degree.”
H. P. Blavatsky
The Mark Of God: Understanding Your "I AM Presence" 