That alchemy reached its apogee during the sixteenth and seventeenth centuries raises interesting questions. How could an occult science predicated on the belief that both matter and the alchemist could be made perfect coexist with the Protestant notion of human depravity or withstand the Counter-Reformation assault on magic? Furthermore, how could an occult and vitalist philosophy gain adherents such as Newton and Leibniz in an age supposedly characterized by Cartesian rationalism and a “mechanical philosophy”?
Alchemy flourished because no other scientific theory explained physical transformations with such plausibility. In addition, it flourished because of the very ideal of perfectionism that led to the censure and execution of some of its practitioners. In an age of bitter sectarian warfare, alchemy provided a refuge for those who clung to the Renaissance concept of a universal philosophy, or prisca theologia, which would unite people in a common quest to restore the world to its prelapsarian perfection. Alchemists were essentially a fifth column within the various denominations; they carried forward the optimistic ideals of Renaissance humanists into the age of the Enlightenment. As a largely educated fifth column, they escaped the worst forms of persecution directed at healers, magicians, and witches. The popularity of alchemy during the scientific revolution supports the increasingly accepted view that one cannot separate science and the occult during this period.
Alchemical theory developed from a mixture of Aristotelian, Neoplatonic, and gnostic philosophy. According to Aristotle every substance consisted of prime matter and a “form.” The form determined the characteristics of the substance, including the proportion of the four elements (earth, air, fire, water), the basic building blocks of matter. Thus an alchemist had only to vary the proportions of the elements or find the “form” of gold to transmute base metal. Alchemists accepted Aristotle's belief that everything in nature has an end (telos). This concept was reinforced by Neoplatonic and gnostic ideas that led many alchemists to envision themselves as saviors of an imperfect world. These “spiritual” alchemists modeled themselves on Hermes Trismegistus, the legendary founder of Western alchemy (hence alchemists were called “hermeticists”). The most famous document supposedly written by Hermes Trismegistus was the Emerald Tablet. The basic message of this enigmatic text is that all things come from one divine nature and will return to it. This idea was enshrined in the alchemical commonplace “All in One” and symbolized by the tail-eating serpent (ouroboros).
European alchemists had little difficulty adopting gnostic ideas because of their apparent compatibility with Christianity. Both are concerned with salvation and describe the experience in terms of death and rebirth. The basic color sequence in alchemy therefore went from black (death) to white (regeneration) to red, the final stage marking the creation of the “royal” stone, which could give perfect life (hence the color of blood) to imperfect substances.
Paracelsus (1493–1541) was the most famous alchemist in the period. While his supporters dubbed him the “Luther of the sciences,” his detractors condemned him as a black magician and gnostic heretic. The mixture of mysticism and practical chemistry in Paracelsus's writings reveals both the heretical nature of alchemy and its importance in the development of modern chemistry. Such a mixture scandalized orthodox Christians. For all their differences, Catholics and Protestants agreed that humans were innately depraved as a result of original sin. The idea that they could redeem themselves and the world was simply heresy.
On a theoretical level, orthodox Christians rejected alchemy and all magic. On a practical level, however, it was not always easy to differentiate black magic from legitimate “natural” magic, or science. The Catholic Church had especial difficulty because some Catholic rituals (exorcism, the blessing of fields, etc.) seemed so close to magic. While the situation should have been easier for Protestants, who considered all forms of magic diabolical attempts to appropriate superhuman powers, they too exempted good, “natural” magic.
For good reasons many Christians ignored the real incompatibility between Christian and alchemical thought. Catholic alchemists identified their transmutations with that of the Eucharist. Lutherans relied on the doctrine of justification by faith to legitimize their role as alchemical saviors. The Calvinist doctrine of election allowed Calvinists to do the same.
Thus the gnostic conviction that humans were sparks of divinity with the power to regenerate themselves and the world led Christian alchemists well beyond the borders of heresy. But it was an idea that could not be eradicated. The gnostic belief in innate human goodness and power, a belief nurtured by alchemists, reached its full development during the Enlightenment and has provided the rationale for liberal and progressive thinking ever since.