Below is the only known reference to the Law of Duality in the writings of Alice A. Bailey (AAB) and Djwhal Khul (DK). Links on these pages of the Laws of Alice A. Bailey are to the online books at the Lucis Trust website.
For a discussion of what AAB means by a “law” please see Alice A. Bailey – What is a Law?
Had the sons of God not “come in unto the daughters of men” (which is the Biblical and symbolic way of expressing the great relationship between spirit and matter which was established in the human kingdom), had the spiritual entities which are humanity itself not taken unto themselves material forms, and had the positive spiritual element not attached itself to the negative material aspect, the present world conflict would not be taking place.But the divine plan of evolution was based upon the production of this relationship between spiritually conscious man and the form aspect, and thus the great Law of Duality came into action, bringing about the “fall of the angels,” as they descended from their sinless and free state of existence in order to develop full divine awareness upon earth, through the medium of material incarnation and the use of the principle of mind. This was the divine plan, emanating from the Mind of God and swept into activity and progressive unfoldment by an act of His Will.
AAB doesn’t give us a lot to go with the Law of Duality, although she does mention “duality” at least 37 times in her writing – here is one example:
“Duality is visioned by the seer. He sees the Presence. He sees, and seeing knows that he exists and likewise that which is seen. … “
“The mystic is ever aware of duality; of the lower man and the indwelling soul; of the tired disciple and the Angel; of the little self and the real Self; of human life expression and of spiritual life expression. Many other qualities stand for the same expression of reality. But, behind them all looms—immanent, stupendous, and glorious—that of which these dualities are but the aspects: the Presence, immanent yet transcendent, of Deity. In the nature of this One, all dualities are absorbed and all distinctions and differences lose their meaning.”
Author Joseph J. Dewey has had some interesting things to say about duality:
If you were able to remove yourself from the world of duality, there would be no truth. Truth can only exist when there is more than one of something. Light can only reveal when a shadow is cast. If you are in space and look through millions of miles of the sun’s rays shining through the void, but with no duality of shadow, there is only blackness. Truth only exists in duality and perception of truth also exists there. If there were such a thing as a world with no duality, there would be no truth for nothing would be there and truth is something.