[259] If Mercurius had been understood simply as quicksilver, there would obviously have been no need for any of the appellations I have listed. The fact that this need arose points to the conclusion that one simple and unmistakable term in no way sufficed to designate what the alchemists had in mind when they spoke of Mercurius. It was certainly quicksilver, but a very special quicksilver, “our” Mercurius, the essence, moisture, or principle behind or within the quicksilver—that indefinable, fascinating, irritating, and elusive thing which attracts an unconscious projection. The “philosophic” Mercurius, this servus fugitivus or cervus fugitivus (fugitive slave or stag), is a highly important unconscious content which, as may be gathered from the few hints we have given, threatens to ramify into a set of far-reaching psychological problems. The concept swells dangerously and we begin to perceive that the end is nowhere in sight. Therefore we would rather not tie this concept prematurely to any special meaning, but shall content ourselves with stating that the philosophic Mercurius, so dear to the alchemist as the transformative substance, is obviously a projection of the unconscious, such as always takes place when the inquiring mind lacks the necessary self-criticism in investigating an unknown quantity.
[260] As has already been indicated, the psychic nature of the arcane substance did not escape the alchemists; indeed, they actually defined it as “spirit” and “soul.” But since these concepts—especially in earlier times—were always ambiguous, we must approach them with caution if we want to gain a moderately clear idea of what the terms spiritus and anima meant in alchemical usage.
[261] Hermes, originally a wind god, and his counterpart the Egyptian Thoth, who “makes the souls to breathe,”1 are the forerunners of the alchemical Mercurius in his aerial aspect. The texts often use the terms pneuma and spiritus in the original concrete sense of “air in motion.” So when Mercurius is described in the Rosarium philosophorum (fifteenth century) as aereus and volans2 (winged), and in Hoghelande (sixteenth century) as totus aereus et spiritualis,3 what is meant is nothing more than a gaseous state of aggregation. Something similar is meant by the poetic expression serenitas aerea in the Ripley Scrowle,4 and by the same author’s statement that Mercurius is changed into wind.5 He is the lapis elevatus cum vento (the stone uplifted by the wind).6 The expressions spirituale corpus7 and spiritus visibilis, tamen impalpabilis8 (visible yet impalpable spirit) might also mean little more than “air” if one recalls the aforementioned vapour-like nature of Mercurius, and the same is probably true even of the spiritus prae cunctis valde purus9 (pre-eminently pure spirit). The designation incombustibilis10 is more doubtful, since this was often synonymous with incorruptibilis and then meant “eternal,” as we shall see later. Penotus (sixteenth century), a pupil of Paracelsus, stresses the corporeal aspect when he says that Mercurius is “nothing other than the spirit of the world become body within the earth.”11 This expression shows better than anything else the contamination—inconceivable to the modern mind—of two separate realms, spirit and matter; for to people in the Middle Ages the spiritus mundi was also the spirit which rules nature, and not just a pervasive gas. We find ourselves in the same dilemma when another author, Mylius, in his Philosophia reformata,12 describes Mercurius as an “intermediate substance” (media substantia), which is evidently synonymous with his concept of the anima media natura13 (soul as intermediate nature), for to him Mercurius was the “spirit and soul of the bodies.”14
[262] “Soul” represents a higher concept than “spirit” in the sense of air or gas. As the “subtle body” or “breath-soul” it means something non-material and finer than mere air. Its essential characteristic is to animate and be animated; it therefore represents the life principle. Mercurius is often designated as anima (hence, as a feminine being, he is also called foemina or virgo), or as nostra anima.15 The nostra here does not mean “our own” soul but, as in aqua nostra, Mercurius noster, corpus nostrum, refers to the arcane substance.
[263] However, anima often appears to be connected with spiritus, or is equated with it.16 For the spirit shares the living quality of the soul, and for this reason Mercurius is often called the spiritus vegetativus17 (spirit of life) or spiritus seminalis.18 A peculiar appellation is found in that seventeenth-century forgery which purports to be the secret book of Abraham le Juif, mentioned by Nicolas Flamel (fourteenth century). The epithet is spiritus Phytonis (from ϕὐω, ‘to procreate,’ ϕυτόν, ‘creature,’ ϕὐτωρ, ‘procreator,’ and Python, the Delphic serpent), and is accompanied by the serpent sign: Ω,19 Very much more material is the definition of Mercurius as a “life-giving power like a glue, holding the world together and standing in the middle between body and spirit.”20 This concept corresponds to Mylius’ definition of Mercurius as the anima media natura. From here it is but a step to the identification of Mercurius with the anima mundi,21 which is how Avicenna had defined him very much earlier (twelfth to thirteenth century). “He is the spirit of the Lord which fills the whole world and in the beginning swam upon the waters. They call him also the spirit of Truth, which is hidden from the world.”22 Another text says that Mercurius is the “supracelestial spirit which is conjoined with the light, and rightly could be called the anima mundi.”23 It is clear from a number of texts that the alchemists related their concept of the anima mundi on the one hand to the world soul in Plato’s Timaeus and on the other to the Holy Spirit, who was present at the Creation and played the role of procreator (ϕὐτωρ), impregnating the waters with the seed of life just as, later, he played a similar role in the obumbratio (overshadowing) of Mary.24 Elsewhere we read that a “life-force dwells in Mercurius non vulgaris, who flies like solid white snow. This is a spirit of the macrocosmic as of the microcosmic world, upon whom, after the anima rationalis, the motion and fluidity of human nature itself depends.”25 The snow represents the purified Mercurius in the state of albedo (= spirituality); here again matter and spirit are identical. Worth noting is the duality of soul caused by the presence of Mercurius: on the one hand the immortal anima rationalis given by God to man, which distinguishes him from animals; on the other hand the mercurial life-soul, which to all appearances is connected with the inflatio or inspiratio of the Holy Spirit. This fundamental duality forms the psychological basis of the two sources of illumination.
[264] In many of the passages it remains doubtful whether spiritus means spirit in an abstract sense.20 It is moderately certain that this is so in Dorn, for he says that “Mercurius possesses the quality of an incorruptible spirit, which is like the soul, and because of its incorruptibility is called intellectual”27—i.e., pertaining to the mundus intelligibilis. One text expressly calls him “spiritual and hyperphysical,”28 and another says that the spirit of Mercurius comes from heaven.29 Laurentius Ventura (sixteenth century) may well have been associating himself with the “Platonis liber quartorum” and hence with the neo-Platonist ideas of the Harranite school when he defined the spirit of Mercurius as “completely and entirely like itself” (sibi omnino similis) and simplex,30 for this Harranite text defines the arcane substance as the res simplex and equates it with God.31
[265] The oldest reference to the mercurial pneuma occurs in an Ostanes quotation of considerable antiquity (possibly pre-Christian), which says: “Go to the streamings of the Nile, and there you will find a stone that has a spirit.”32 In Zosimos Mercurius is characterized as incorporeal (ἀσὠματον),33 and by another author as ethereal (αἰϑερῶδες πνεῡμα) and as having become rational or wise (σὠϕρων γενομἐνη).34 In the very old treatise “Isis to Horus” (first century) the divine water is brought by an angel and is clearly of celestial or possibly daemonic origin, since according to the text the angel Amnael who brings it is not a morally irreproachable figure.35 For the alchemists, as we know not only from the ancient but also from the later writers, Mercurius as the arcane substance had a more or less secret connection with the goddess of love. In the “Book of Krates,” which was transmitted by the Arabs and is possibly of Alexandrian origin, Aphrodite appears with a vessel from the mouth of which pours a ceaseless stream of quicksilver,36 and in the Chymical Wedding of Christian Rosencreutz the central mystery is his visit to the secret chamber of the sleeping Venus.
[266] The fact that Mercurius is interpreted as spirit and soul, in spite of the spirit-body dilemma which this involves, indicates that the alchemists themselves conceived of their arcane substance as something that we today would call a psychic phenomenon. Indeed, whatever else spirit and soul may be, from the phenomenological point of view they are psychic structures. The alchemists never tired of drawing attention to the psychic nature of Mercurius. So far we have concerned ourselves with, statistically, the commonest synonyms such as water and fire, spirit and soul, and it is now possible for us to conclude that these exemplify a psychological state of affairs best characterized by (or, indeed, actually demanding) an antinomian nomenclature. Water and fire are classic opposites and can be valid definitions of one and the same thing only if this thing unites in itself the contrary qualities of water and fire. The psychologem “Mercurius” must therefore possess an essentially antinomian dual nature.