In his time, Artemidorus Daldianus was a highly regarded man. He was a dream doctor, and in the second century A.D. his fellow Greeks considered dreams to be encoded messages from the gods. Deciphering them required an expert, with Artemidorus chief among them.
Artemidorus declared that all dreams were not created equal, however. If the nocturnal visions could be explained from past events in the sleeper's life, the good doctor wrote them off as meaningless constructions of the individual's experiences and mental orientation; these dreams were not secrets of the gods. Artemidorus himself would never have imagined that, with this idea, he had anticipated a core debate that would arise some 1,700 years later.