Beck's case for reading the mithraeum as a working model of the cosmos rests on more than the cave shape and the star ceiling, it rests on the order of the seven grades of initiation matching, degree for degree, the order of the seven classical planetary spheres as ancient astronomy arranged them outward from earth. Raven corresponds to Mercury, Bride to Venus, Soldier to Mars, Lion to Jupiter, Persian to the Moon, Sun Runner to the Sun itself, and Father, the highest grade, to Saturn, the outermost and coldest sphere in the ancient scheme. If the correspondence is deliberate, an initiate moving up through the grades was moving, symbolically, up through the planetary spheres toward the fixed stars beyond them, the ascent Porphyry describes souls making through the cave's gates.
Critics of the reading point out that the correspondence survives mainly in a handful of later, non Mithraic sources rather than in an explicit Mithraic text stating it outright, and that reconstructing a lost theology from an assumed astronomical grid risks finding the pattern because it was being looked for. Both sides agree on the archaeology, the caves, the ceilings, the seven named grades themselves, all independently attested. What divides them is how much interpretive weight a silent structure can bear when the initiates who used it left no doctrinal text of their own explaining what it meant to them.