The Three Parts of Wisdom
The threefold philosophy of alchemy, astrology, and theurgy.
Hermes is called Thrice-Great because he possessed the three parts of philosophy: alchemy (transformation of matter and self), astrology (knowledge of cosmic correspondences), and theurgy (divine magic and spiritual development).
Having the three parts of the philosophy of the whole world.
These three arts together form the complete Hermetic curriculum.
The Emerald Tablet