They represent a trinity in unity, three in one--the same in essence, though multiform in office: God the Father; Christ the type of Sonship; Divine Science, or the Holy Comforter....
"The Holy Ghost, or Spirit, reveals this triune Principle, and (the Holy Ghost) is expressed in Divine Science, which is the Comforter, leading into all Truth, and revealing the divine Principle of the universe--universal and perpetual harmony." I will cite another passage.

Speaking of Jesus-- "His students then received the Holy Ghost.

By this is meant, that by all they had witnessed and suffered they were roused to an enlarged understanding of Divine Science, even to the spiritual interpretation..
...

of His teachings," etc.
Also, page 579, in the chapter called the Glossary: "HOLY GHOST.

Divine Science; the developments of Life, Truth, and Love." The Holy Ghost reveals the massed spirit of the fused trinity; this massed spirit is expressed in Divine Science, and is the Comforter; Divine Science conveys to men the "spiritual interpretation" of the Saviour's teachings.