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 shoot-ing 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 re-jected thing, 'thrown out into the street," "cast on the dung-hill," "found in filth.' These epithets reflect not only the per-plexity of the investigator but also his psychic background, which animates the darkness lying before him, so that he discov-ers in the projection the qualities of the unconscious.
— C. G. Jung
The thousand names are not a failure of classification — they are the point. What cannot be named once is the thing that keeps slipping past every frame you have built to contain it. Jung's alchemists were not confused; they were accurately reporting the behavior of something that refuses fixity, and the tradition honored that refusal by multiplying synonyms rather than collapsing them into a definition.
What the passage makes visible is the logic underneath the work: you cannot start until you have found what you cannot recognize. That structure is not a puzzle to be solved but a description of how the unconscious actually behaves toward the ego that goes looking for it. The darkness doesn't withhold itself out of hostility — it is genuinely prior to the concepts you would use to retrieve it. The alchemist's "perplexity" is not a stage on the way to clarity; it is the epistemically correct response to standing in front of something that will animate itself through your projections before it allows any other form of knowing.
Cast on the dung-hill, thrown into the street: the psyche hides the load-bearing material in what you have already decided doesn't matter. The investigation always begins in the wrong place, which is to say the only place it can begin.
C. G. Jung·Collected Works Volume 3: The Psychogenesis of Mental Disease·1907