So many thousands of years have passed and so many scholars have written about the ancient gods and deities that it is difficult to decipher the being known as Hermes Trismegistus and separate fiction from fact. Unfortunately, conflicting views exist on whether Hermes Trismegistus was a man or a god. Frances A. Yates suggests those living in Renaissance times believed he was a man: "It was on excellent authority that the Renaissance accepted Hermes  Trismegistus as a real person of great antiquity and as the author of the Hermetic writings." A city known as Hermopolis that existed in Egypt in ancient times strengthens the claim.

Other scholars conjecture that different individuals completed the Hermetic writings over several hundred years. Perhaps the most important piece of evidence to back up this claim is the Syrian philosopher Iamblichus crediting Hermes with writing over 20,000 books and an Egyptian priest named Manetho crediting him with writing more than 36,000 books. Both of these men lived around 250-300 BC. Iamblichus went on to state he had seen   forty-two of these books, thirty-six of which contained "the whole of human knowledge".

Many scholars have long held Hermes Trismegistus to be the equivalent of the Egyptian god Thoth, which certainly suggests he was not a real person. Frans A. Janssen subscribes to this view, describing Hermes Trismegistus as a "fictitious author" in his essay Dutch Translations of the Corpus Hermeticum. Anecdotal evidence suggests that Hermes was a man elevated to deity status and even if Hermes Trismegistus did not write the texts attributed to him, it is likely that a priest of the Egyptian god Thoth did. Others, such as Stock, state that Hermes Trismegistus was actually the grandson of the Hellenistic god Hermes, the messenger of the gods.