There are 8 Schools of Magic which can further be divided into 2 aspects - physical and spiritual.
The Schools of Invocation, Alteration, and Warding fell within the physical aspect of magic. Whereas, the Schools of Enchantment, Illusion, and Divination fell under the spiritual aspect of Magic.
Meanwhile, the two remaining Schools of Magic—Summoning and Necromancy—were considered special. In that, they belonged to both aspects of magic.
In the past, whenever Adam cast spells from the Schools of Illusion, Enchantment, Divination, and Summoning, he always felt that the existence of the white lotus strengthened the output of these spells.
This led him to believe that the lotus had some connection to the spiritual aspect of magic.
However, it wasn't until he had delved deeper into the mysteries of the white lotus, that he realized that it wasn't the spiritual aspect of magic that it was connected to, but the Spirit World itself.