Isis as a mystery upThe unveiling of a statue of Isis as a personification of nature, depicted as the climactic moment of an Isiac initiation, in an 1803 engraving by Henry FuseliAssmann 1997, pp. 134–135 Another interpretation of Isis's veil emerged in the late 18th century, in keeping with the Romantic movement that was developing at the time, in which nature constitutes an awe-inspiring mystery rather than prosaic knowledge. Hadot 2006, pp. 318–319 This interpretation was influenced by the ancient mystery initiations dedicated to Isis that were performed in the Greco-Roman world. Assmann 1997, pp. 126–134 Although these rites were developed in Hellenistic or Roman times, under the influence of earlier Greco-Roman mystery rites, Bremmer 2014, pp. 110–114 both classical authors and 18th-century scholars assumed them to have been age-old features of ancient Egyptian religion. Macpherson 2004, pp. 241–245 Many Freemasons, members of a European fraternal organization that attained its modern form in the early 18th century, adopted Egyptian motifs and came to believe their rituals could be traced back to the mysteries of Isis. Macpherson 2004, pp. 245–248 One Freemason in the 1780s, Karl Leonhard Reinhold, tried to reconcile Freemasonry's traditional origin story, which traces Freemasonry back to ancient Israel, with its enthusiasm for Egyptian themes. To do so, he interpreted the first statement on the statue at Sais, "I am all that has been and is and shall be," as a declaration of pantheism, in which nature and divinity are identical. Reinhold claimed the public face of Egyptian religion was polytheistic, but the Egyptian mysteries were designed to reveal the deeper, pantheistic truth to elite initiates. He also said the statement "I am that I am", spoken by the Jewish God in the Book of Exodus, meant the same as the Saite inscription and indicated that Judaism was a descendant of the ancient Egyptian belief system. Assmann 1997, pp. 115–125 Under the influence of Reinhold's interpretation, other Freemasons came to see the veiled Isis as a symbol of an impenetrable enigma, representing truth and being as well as nature, Hadot 2004, pp. 267–269 a deity that, as Assmann puts it, was regarded as "too all-encompassing to have a name." Assmann 1997, p. 120 Immanuel Kant connected the motif of Isis's veil with his concept of the sublime, saying, "Perhaps no one has said anything more sublime, or expressed a thought more sublimely, than in that inscription on the temple of Isis (Mother Nature)." According to Kant, the sublime evoked both wonder and terror, and these emotions appeared frequently in the works of late 18th and early 19th-century authors using the motif of the veil. The ecstatic nature of ancient mystery rites themselves contributed to the focus on emotions. Hadot 2004, pp. 269–283 Friedrich Schiller, for instance, wrote an essay on Egyptian and Jewish religion that mostly copied Reinhold's work but put a new emphasis on the emotional buildup that surrounded the mysteries. He said it prepared the initiate to confront the awe-inspiring power of nature at the climax of the rite. Similarly, a frontispiece by Henry Fuseli, made for Erasmus Darwin's poem The Temple of Nature in 1803, explicitly shows the unveiling of a statue of Isis as the climax of the initiation. Helena Blavatsky's 1877 book Isis Unveiled, one of the foundational texts for the esoteric belief system of Theosophy, used the metaphor of the veil as its title. Isis is not prominent in the book, but in it Blavatsky said that philosophers try to lift the veil of Isis, or nature, but see only her physical forms. She added, "The soul within escapes their view; and the Divine Mother has no answer for them," implying that Theosophy would reveal truths about nature that science and philosophy could not. Ziolkowski 2008, pp. 75–76
Isis as a mystery upThe unveiling of a statue of Isis as a personification of nature, depicted as the climactic moment of an Isiac initiation, in an 1803 engraving by Henry Fuseli Another interpretation of Isis's veil emerged in the late 18th century, in keeping with the Romantic movement that was developing at the time, in which nature constitutes an awe-inspiring mystery rather than prosaic knowledge. This interpretation was influenced by the ancient mystery initiations dedicated to Isis that were performed in the Greco-Roman world. Although these rites were developed in Hellenistic or Roman times, under the influence of earlier Greco-Roman mystery rites, both classical authors and 18th-century scholars assumed them to have been age-old features of ancient Egyptian religion. Many Freemasons, members of a European fraternal organization that attained its modern form in the early 18th century, adopted Egyptian motifs and came to believe their rituals could be traced back to the mysteries of Isis. One Freemason in the 1780s, Karl Leonhard Reinhold, tried to reconcile Freemasonry's traditional origin story, which traces Freemasonry back to ancient Israel, with its enthusiasm for Egyptian themes. To do so, he interpreted the first statement on the statue at Sais, "I am all that has been and is and shall be," as a declaration of pantheism, in which nature and divinity are identical. Reinhold claimed the public face of Egyptian religion was polytheistic, but the Egyptian mysteries were designed to reveal the deeper, pantheistic truth to elite initiates. He also said the statement "I am that I am", spoken by the Jewish God in the Book of Exodus, meant the same as the Saite inscription and indicated that Judaism was a descendant of the ancient Egyptian belief system. Under the influence of Reinhold's interpretation, other Freemasons came to see the veiled Isis as a symbol of an impenetrable enigma, representing truth and being as well as nature, a deity that, as Assmann puts it, was regarded as "too all-encompassing to have a name." Immanuel Kant connected the motif of Isis's veil with his concept of the sublime, saying, "Perhaps no one has said anything more sublime, or expressed a thought more sublimely, than in that inscription on the temple of Isis (Mother Nature)." According to Kant, the sublime evoked both wonder and terror, and these emotions appeared frequently in the works of late 18th and early 19th-century authors using the motif of the veil. The ecstatic nature of ancient mystery rites themselves contributed to the focus on emotions. Friedrich Schiller, for instance, wrote an essay on Egyptian and Jewish religion that mostly copied Reinhold's work but put a new emphasis on the emotional buildup that surrounded the mysteries. He said it prepared the initiate to confront the awe-inspiring power of nature at the climax of the rite. Similarly, a frontispiece by Henry Fuseli, made for Erasmus Darwin's poem The Temple of Nature in 1803, explicitly shows the unveiling of a statue of Isis as the climax of the initiation. Helena Blavatsky's 1877 book Isis Unveiled, one of the foundational texts for the esoteric belief system of Theosophy, used the metaphor of the veil as its title. Isis is not prominent in the book, but in it Blavatsky said that philosophers try to lift the veil of Isis, or nature, but see only her physical forms. She added, "The soul within escapes their view; and the Divine Mother has no answer for them," implying that Theosophy would reveal truths about nature that science and philosophy could not. 
R
FuseliAssmann 1997, pp. 134–135
Fuseli
D
Hadot 2006, pp. 318–319
D
Assmann 1997, pp. 126–134
D
Bremmer 2014, pp. 110–114
D
Macpherson 2004, pp. 241–245
D
Macpherson 2004, pp. 245–248
D
Assmann 1997, pp. 115–125
D
Hadot 2004, pp. 267–269
D
Assmann 1997, p. 120
D
Hadot 2004, pp. 269–283
D
Ziolkowski 2008, pp. 75–76