(Plato's) Socrates, in Cratylus, argues that Persephone should correctly be called something like Pherepapha (404c-e), because her real name (cited, confusingly, as Pherrephatta, shows that she is wise:
For since things are swept along (φερόμενα), wisdom is the power to grasp (ἐφαπτόμενον), comprehend, (ἐπαφῶν), and to follow (ἐπακολουθεῖν) them. Thus it would be correct to call this goddess ‘Pherepapha’ or something like that, because of her wisdom, that is to say, her power to comprehend what is being swept along (ἐπαφὴ τοῦ φερομένου). (Plat. Crat. 404c-d, trans. Reeve.)
Fear, Socrates explains, leads to wilful errors of naming and the employment of alternative spellings in an effort to disguise the true meaning of the name. The correctness (or, more accurately, the incorrectness) of Plato’s etymology does not alter the point: people were afraid of the goddess and changed her name to make her somehow more palatable. Persephone is near-interchangeable with Kore, and the chorus of Euripides’s Helen calls Persephone the ἀρρήτου κούρας (‘unspoken girl’ Eur. Hel. 1306-1307; cf. fr. 63 (Kovaks)); these all add up to the same affect: renaming the goddess changes her power in some way. Rudolf Wachter argued that the ‘original’ name we should look for is more like Φερρῶφαττα (with either an omega or omicron in place of the epsilon), for which there are nine attestations. Seven of these are found on fifth-century Attic vases, by individual painters. This shows an etymology with ‘she who threshes ears of corn’, but this does not directly presuppose a Frazer-esque Corn Maiden. Perrophatta is not an embodiment of corn, but an intermediary between Demeter and the people, ensuring agriculture – her mother’s gift – is received. When Pherrephatta retreats beneath the earth, seeds also retreat. Here, both goddess and seeds mature and grow, before sprouting forth to bring life to the people. In this incarnation, Persephone is not a submissive and deferential divinity, hiding behind her mother or husband. She is an active participant in the life-cycle of grain, and therefore of the earth and its population.
There is an interesting parallel her to Hades, who is also mention by Socrates (Crat. 403a), although here we find Hades being renamed as another god - Plouton. Hades was an absent god - he's almost absent from cultic life (the notable exception is his cult in Elis). The etymology of 'Hades' points to something like 'unseen one' or 'the invisible'. Although Hades is obviously not the only god who is unseeable to mortals, since many Olympic gods appear invisible, and are often not directly seeable in cult as well. But other gods make themselves invisible and Hades is (nearly) always invisible. Not, I should note, imperceptible, but that under certainly conditions (namely, being alive) he is concealed. One may see him clearly but only after death.
This reputation might have been perpetuated by his mythic 'cap of invisibility' - first found in Homer, when Athena uses it to hide herself from Ares (Il. 5.8.44-845.) According to pseudo-Apollodoros, the Kyklopes gave 'Plouton' (note the renaming) when he gave Zeus the thunderbolt and Poseidon the trident, which would mean that it was an inextricable part of his character (Bibl. 1.2.1.). Hesiod also mentions the cap, but here it does not make the wearer invisible, but cloaks him with the νυκτὸς ζόφον αἰνὸν (‘awful gloom of night’ Sh. 227.). Night and darkness are well associated, particularly in Homer were dying heroes are described as having night or darkness descend upon them or cover their eyes (e.g. Hom. Il. 5.659). The juxtaposition between dark and light is the same as the juxtaposition between the living and the dead: the living man sees and the dead man is shrouded in darkness. Darkness is a natural attribute of invisibility. The Underworld - and therefore Hades - is shrouded in darkness, and the dead are invisible to the living.
Fear may have much to do with the unnaming and renaming of both Persephone and Hades, and they are both stifled of (or stifling of) mortal senses: Hades cannot be seen, and Persephone cannot be heard - this is an obviously simplistic view of naming (unnaming, renaming), but I wanted to get some of these basics down quickly, because in the next few posts I am going to go into some more detail on various aspects of Persephone and Hades (and particularly their unnaming and renaming), so I would be interested to hear any initial thoughts before those posts come out.