The ritual instructions for the famous Mithras Liturgy tell the magician to begin the complex preparations for the encounter with the supreme sun god Mithras "at the seizure of the moon," that is, at the time of the new moon, when the moon is absent from the heavens. This absence of the moon is not merely an isolated ritual detail, but rather it corresponds to a pattern throughout the whole spell, in which the absence of the moon is crucial to the magician's project of immortalization through his contact with the powers of the sun. This pattern reveals the significance of the sun and moon in the cosmology of the compiler of the Great Paris Magical Papyrus.
Not only must the magic ointment of immortalization be prepared at the new moon, but other ritual preparations must be done "at the time of the new moon in the Lion," again, in the absence of the moon. The moon is not merely absent from the ritual preparations, but even from the experience of the magician in the spell itself. As the magician ascends through the cosmos on the rays of the sun to the encounter with the supreme god, he (or she) passes through the air and winds, the planets and stars, and the doors of the sun. In this journey, the moon is conspicuously absent from her place at the nexus of the mundane world and the celestial world of planets and stars. Although the magician addresses prayers to the planets and stars and to the deities of the sun to speed the journey, no prayer appeals to the power of the moon.
The significance of the moon's absence from the Mithras Liturgy lies in the moon's role as a power of genesis, of bringing souls down from the upper realms into the world below. In his Cave of the Nymphs, Porphyry links the process of apogenesis to the sun and that of genesis to the moon. "The theologians make the 'gates' of souls the sun and the moon, the ascent taking place through the sun and the descent through the moon." (Porphyry 29, On the Cave of the Nymphs, Robert Lamberton, trans., Station Hill Press: Barrytown, New York, 1983, p. 37.) Contrasts with different Neoplatonist cosmologies and with the ideas of Mithraism as represented in the surviving monuments show that the cosmology of the Mithras Liturgy assigns an unusually negative role to the moon and the process of genesis. While in other Neoplatonic theurgical systems, such as the Chaldaean Oracles, the moon can play a positive role for the theurgist seeking to connect with the higher realms, in the Mithras Liturgy the magician must avoid the presence of the moon in the voyage upon the rays of the sun up to the highest god. Only the powers of apogenesis are invoked in this spell, and any hint of the powers of genesis must be excluded.
This separation within the Mithras Liturgy parallels the organization of the Great Paris Magical Papyrus itself. The Mithras Liturgy, lines 475-829 of the papyrus, comes in the first section of the papyrus, which contains a number of spells that invoke or appeal to the power of the sun, under various epithets. None of these spells invoke the moon in any aspect. By contrast, the final section of the papyrus contains a number of spells invoking the moon as Selene, Hekate, Artemis, Persephone, or other underworld goddess, and it contains none of the invocations to Helios common in the first part of the papyrus. The papyrus is roughly divided into sun spells and moon spells, showing that the compiler of the papyrus thought of solar and lunar invocations as separate categories.
The curious absence of the moon in the Mithras Liturgy in the ritual timing, in the magician's voyage through the heavens, and even in the organization of the papyrus, provides an insight into the cosmology underlying the spell. The supreme god, invoked as Mithras Helios, is a solar deity who can redeem the magician from genesis, while the moon represents the powers of genesis, whose influence must be kept away from the process of immortalization.