Popularly, alchemists refer to those who engaged in pre-scientific chemical experimentation. The driving quest of alchemy was said to be that of transmuting metals, particularly base metals (e.g. lead) into noble ones (e.g. gold). So, alchemists are also those who are engaged in any transformation process, particularly those which cannot be explained by the laws of nature.
Whilst many alchemical works may be considered solely as a prelude to chemistry, there are a number of works in which alchemy is looked upon as both an operational and spiritual technique. The language of chemistry employed by the genuine alchemists is understood to be a metaphor for the work of psychic transmutation. The transmutation of base metals into gold is the transmutation of psychophysical elements within man from an impure, obstructed state to a fine state of responsiveness to high-frequency energy. The principal, or underlying, intent of alchemy is then understood as one of making of the body a spirit and of the spirit a body through transmuting the bodily consciousness into spirit and through fixing the spirit in the body. This assumes the possibility of changing the "state of aggregation" of a body in conformity with the metallurgical symbolism that is used to describe the process.
In most traditions, alchemy is none other than the science through which the sacred nature of rhythm was expressed and the link to eternity established. It acquired a special significance in the monotheistic traditions, especially Christianity. Through its more general expression in the form of hermeticism, it was the only cosmological doctrine to survive in the Christian world, complementing Christianity up to the appearance of Gothic art. Despite the insistence of historians of science, alchemy was never, except in its degenerate aspects, a primitive form of chemistry. The importance of alchemy lies in its emphasis on the divine omnipresence in the depths of material heaviness, where it appears least likely to become apparent. The most detailed overview of alchemical processes and traditional imagery is that by a modern author writing under the traditional pseudonym of Johannes Fabricius.
Two broad meanings of alchemy are extant:
1. Alchemy as the activity of obtaining an agent of transmutation, variously and allegorically named, in the form of a liquid elixir, a powder of projection, or a solid 'stone'. It is a practice associated with the preparations of medicines in the internal alchemy of producing and maintaining a healthy, long-living human body, and therefore also with a healthy psychology. The internal alchemy ultimately broadened its aims from long, healthy life, to immortality; and from a healthy psychology to a quest for superhuman knowledge and powers. In the latter form it became a species of magic. In both forms it has been associated with delusion and charlatanism. In some aspects its practices required astrological considerations, and in others religious piety.
For example, the so-called "outer alchemy" of Taoism sought to achieve physical immortality through means of an elixir or pill produced by alchemical means - repeated reductions and recyclings to produce purified mercuric sulphide from the cinnabar ore. Nine-times purified cinnabar was then ingested followed by a combination of meditative breathing and sexual techniques echo the reduction and recycling process through the process of circulation of essence through the body, strengthening and replenishing of ch'i (vital energy) and resulting in the formation of the sacred and immortal embryo or soul.
2. A second, but not unrelated, meaning of alchemy is to practice an occult art or spiritual discipline, one of whose objects is to provide a subtle vehicle for the soul, a second, spiritual body. For this purpose the physical body is viewed as a chemical chamber or vessel of some kind, for example, a distillation flask, or, from more of a metallurgical point of view, as a furnace or crucible which is subjected to the firing and within which transmutation takes place. The "firing process" is a metaphor employed in alchemical texts for the order of practical spiritual work.
In Taoism, it is through the firing process that the encrustations of the faculties are burnt away to expose the awareness of the original spirit - shen. This requires an appropriate combination over time of inward discipline (originally meditative techniques), application of effort and other techniques. Finally the self is integrated with the universe as the mind is purified and returns to nothingness. Different meditative techniques have evolved with these ends in view, some clearly viewing the whole process as spiritual while others adopt more physical manifestations of the spiritual process (e.g. breathing, sexual intercourse) to achieve the desired result, which may be reduced thereby to a desire for physical longevity:
In Tibetan Sakya Buddhism, a stage of empowerment into the Supreme (anuttara) Tantra is represented as a flask or alchemical vessel from the later contents of which will grow the form of Buddhahood called the emanation-body (nirmana-kaya, sprul-sku). In the initiation, an actual flash is filled with amrita, the sacred potion of some 25 ingredients compounded with water and spiritual power, which is drunk by the candidate. Thereafter he enters the mandala of the ritual which represents the consciousnesses that he is encountering.
Jung saw the symbolic aspects of alchemy as a precursor of modern study of the unconscious and the transformation of personality; and its goals as metaphors for psychological growth and development. The combination of two opposite elements resulting in a new entity - seen symbolically as the conjunction of male and female producing an infant - are particularly clear symbols of the intrapsychic processes and the development of the individual personality. The unconscious undergoes processes which express themselves in alchemical symbolism, tending towards psychic results which correspond to the results of hermetic operations. Dreams or waking dreams containing alchemical symbols constitute a series, the development of which accompanies a process of individuation.