"Many a magician has lost his life as the result of opening a way whereby submundane creatures could become active participants in his affairs. When Eliphas Levi invoked the spirit of Apollonius of Tyana, what did he hope to accomplish? Is the gratification of curiosity a motive sufficient to warrant the devotion of an entire lifetime to a dangerous and unprofitable pursuit? If the living Apollonius refused to divulge his secrets to the profane, is there any probability that after death he would disclose them to the curious-minded? Levi himself did not dare to assert that the specter which appeared to him was actually the great philosopher, for Levi realized only too well the proclivity of elementals to impersonate those who have passed on. The majority of modern mediumistic apparitions are but elemental creatures masquerading through bodies composed of thought substance supplied by the very persons desiring to behold these wraiths of decarnate beings."
- Manly P. Hall