Giovanni Pontano (1426/1503) wrote a famous alchemical text that is titled The PHILOSOPHICAL FIRE in which he explains how he found the way to spiritual alchemy.
Although at first he tried to produce the stone with material experiments, he finally understood that the stone was not a material object but an heavenly or spiritual one. He wrote:
"I, John Pontanus, have traveled through many countries, in order to know the certainty of the Philosophers' Stone: and I found many impostors, but not true philosophers... until I finally found the truth."
"First, I started with the putrefaction of the matter, which I continued for nine months, and I got nothing. Afterwards, I tried for a while a "Balneum Marie", but in vain. After that I used a calcination fire for three months, and I still found myself off the Track. I tried all kinds of distillations and sublimations, as the philosophers Geber, Archelaus, and all the rest of them have prescribed, and I still found nothing: in short, I tried to perfect the whole work of alchemy by all imaginable and plausible means... baths, ashes, and other heats of various kinds, all of which are found in the books of the philosophers, still unsuccessful." "I studied, however, in the books of the philosophers, and especially in Hermes, whose concise words comprehend the sum of all matter, that is, the secret of the Philosopher's Stone, by an obscure manner of speaking, of what is superior, and what is inferior, namely, of Heaven and Earth."
What is the Philosopher's Stone (lapis philosophorum)?
If the stone is not material, one must look for it in the spiritual field. Because it has four qualities, water, earth, fire and air, we must understand that the stone is related to consciousness. It is well known that the four elements of astrology are psychological types and ways to interact with the environment. They are the direct precursors of C. G. Jung's four cognitive functions Feeling, Sensation, Thinking and Intuition. It has been often underlined by Jung and his followers that people generally fully develop only one cognitive function and, partially, an auxiliary one. The other two are almost never used. Therefore, the stone is the perfecting of consciousness by the development of all four cognitive functions which becomes the philosophical fire. Potato wrote:
"The Lapis Philosophorum, therefore, is but one, although it has many names, which, before you conceive them, it will be very difficult for you to understand. For it is watery, aerial, igneous, terrestrial; it is Salt, Sulphur, Mercury and Phlegm; it is sulphurous, and yet it is Living Silver; it has many superfluities, which are changed in the true essence by the help of Our Fire."
It is the personal wisdom of the Sophical Fire and our Fire is "The Greatest Secret, Alchemy".
Sulphur, Mercury, Salt and Phlegm are the designations by which we state the position of each cognitive function. They correspond to the terms dominant, auxiliary, tertiary and inferior in JUNGIAN psychology. Pontano adds
"It is possible to transmute into the perfect body that which is superfluous, filthy and dirty is transmuted thanks to the Sophical Fire, into something fixed and spiritual; our fire, "which is not fire" but acts like it: but our fire transmutes and changes the whole subject into purity. "
"The error, therefore, in this work, proceeds chiefly from not knowing or understanding the True Fire, which is one of the moving principles which transmutes all matter into the true stone of the philosophers; therefore, seek him diligently."
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To learn more, please refer to my book
The KEY to Understand C. G. Jung,
available HERE on AMAZON.