How is it possible ? We know it is possible, but how ? Here is the most important secret in Alchemy, in spirituality. It deals with a how, and a where also.
How, when, where, by who is this secret possible ?
All the answers are in Nature. Where, if not in the Nature ? The first of all Alchemist may have found the Stone by accident, or maybe he found the laws first. But something is for sure : he wasn't initiated by some order or philosopher before, BUT, he was allowed (he had the ticket for the Stone) by the superior intelligence, Nature Her/Itself.
Maybe you see Nature, but you don't look, change your perspective, your point of view, your ideas, your vision, try another angle. Maybe you will grasp some truth.
It is very difficult to actually understand Nature. The human race tried it. Nowadays vision understand Nature from a "dead" point of view, there is only with quantum physics that Life can come again to the surface, but since it is not something you can hold in your hand ...
An Alchemist deals with the volatile, ungraspable, and he tries to fix it. Maier was very aware of this, and we can see it clearly in his emblem.
At some point of your travel, you loose your desire for the Stone. You also loose your desire for healing, yourself or others, and for transmutation, or any kind of "powers". Surprisingly, it is then that all these things tend to come to you. "You passed the audition" would say a friend of mine. You saw the gate keeper, the Dragon, and he lets you go into the cave, to find the treasure and the Princess. His breath is no more deadly for you since you master all the desires he represents. All the dangers are mastered. You don't loose your goals or interests, but you loose your desires, your passion, and your emotions.