Jung on Alchemy

My results, based on fifteen years of effort, seemed inconclusive, because no possibility of comparison offered itself. I knew of no realm of human experience with which I might have backed up my findings with some degree of assurance. The only analogies-and these, I must say, were far removed in time-I found scattered among the reports of the heresiologists. This connection did not in any way ease my task; on the contrary, it made it more difficult, because the Gnostic systems consist only in small part of immediate psychic experiences, the greater part being speculative and systematizing recensions.

Carl Jung, Alchemical Studies