The Seba library treats Cap in 5 passages, across 4 authors (including Eliade, Mircea, Jung, C.G., Onians, R B).
In the library
5 passages
a great part of their power is hidden in these caps... shamanizing without a cap, they were deprived of all real power and that hence the whole ceremony was only a parody
Eliade establishes the shamanic cap as a literal vessel of sacred power, without which ritual efficacy collapses into theatrical simulation.
Eliade, Mircea, Shamanism: Archaic Techniques of Ecstasy, 1951thesis
After these scenes in the dream he goes downstairs with his wife and hunts for his hat, which he cannot find
The lost hat in the dream context signals a disruption or failure of the dreamer's persona, connecting headgear to the psychological function of social identity.
Jung, C.G., Dream Analysis: Notes of the Seminar Given in 1928-1930, 1984supporting
one who looked after his genius, eating a great deal, was not only termed genialis but in Plautus' time was nicknamed 'Capito', 'Head', as if that were all that mattered
Onians documents the Latin nickname 'Capito' as evidence that the head was culturally identified with the life-soul and genius, lending archaic depth to what crowns or caps the head.
Onians, R B, The origins of European thought about the body, the mind,, 1988supporting
Kap [n.] indecl. 'head', only in ἐπὶ κap 'on its head, topsy-turvy'
Beekes records the rare Greek form 'Kap' meaning 'head,' providing etymological grounding for the semantic link between cap, covering, and the head as conceptual apex.
Beekes, Robert, Etymological Dictionary of Greek, 2010aside