Tat, in Hermeticism, is the son of Hermes Trismegistus (CH. XIV, 1). In CH XIII, 9, we learn that Hermes is incapable of teaching Tat the most complex aspects of his teachings because Tat is too young for this. Tat may have learned these lessons later which would tie in with his later role as master (CH. XVII).
Tat may symbolize the early stages of the student’s hermetic path. In CH. XIII, 7-10, his mortal weaknesses are purified by God’s power.
In CH. XIII, 2 Tat says that the doctrine between father and son has no riddles. The language used by Hermes in Tat’s lessons is therefore always simple and clear. The chapters in which Hermes instructs his son are therefore good to read by novice Hermeticists.
Tat stands for the self learning ability. Hermes, Thoth and Tat all refer to aspects of the same divine presence. They refer to the different levels of spiritual and spiritual education.
Who learns from whom? If you want to grow in knowledge, both worldly knowledge and spiritual knowledge, you will have to continue to learn and experience.
You can experience Tat’s presence in your life by observing when you feel the inner urge to want to learn and to seek knowledge and wisdom.