The prima materia is, as one can so aptly say in English, "tantalizing": it is cheap as dirt and can be had everywhere, only nobody knows it; it is as vague and evasive as the lapis that is to be produced from it; it has a "thousand names." And the worst thing is that without it the work cannot even be begun. The task of the alchemist is obviously like shooting an arrow through a thread hung up in a cloud, as Spitteler says. The prima materia is "saturnine," and the malefic Saturn is the abode of the devil, or again it is the most despised and rejected thing, "thrown out into the street," "cast on the dunghill," "found in filth." These epithets reflect not only the perplexity of the investigator but also his psychic background, which animates the darkness lying before him, so that he discovers in the projection the qualities of the unconscious. This easily demonstrable fact helps to elucidate the darkness that shrouds his spiritual endeavours and the labor Sophiae: it is a process of coming to terms with the unconscious, which always sets in when a man is confronted with its darkness. This confrontation forced itself on the alchemist as soon as he made a serious effort to find the prima materia.
— Carl Gustav Jung
Saturn rules this passage for a reason. The alchemists identified the prima materia with what culture had already declared worthless — dunghill, street filth, the thing nobody picks up — and the identification is not metaphor. It is diagnosis. What you most need cannot be purchased in the register where need is usually met; it cannot be recognized by the part of you that is already organized, already oriented toward a goal. The thousand names signal this. Any single name would let you aim. A thousand names means the thing refuses to be fixed as object, which is exactly the condition that makes it prior to all objects — the raw stuff that must be worked before anything else can be worked.
The alchemist's perplexity was not stupidity. It was the discovery, through projection, that the darkness confronting him was interior darkness — the unconscious animating the material he was handling. He did not begin with that knowledge; he arrived at it by failing to find what he expected. The labor only became the *labor Sophiae* — wisdom's work — when the confrontation forced itself. Nothing prior to that force makes the beginning possible. This is why Saturn presides: not as punishment, but as the planet of what will not yield until you stop trying to get around it.
Carl Gustav Jung·Alchemical Studies·1967