Spoiler for lengthy speculations
Spoiler
However, FiM traditionally draws more on Greek mythology than on Christian or Hebrew traditions, perhaps indicating that the ancient civilisation of Equestria was in some way an analogue of Ancient Greece. So perhaps for the origin of the element of kindness we should look towards Charis, the Greek personification of kindness, and one of the Charites (the Graces). Charis is often used to refer to any of the three Charites, but is particularly associated with the youngest, whom Hesiod in his Theogny calls Aglaea (meaning 'shining') who was an attendant of Aphrodite (goddess of love), wife of Hephaestus (the blacksmith god of fires and craftsmanship), and mother of personifications of glory/fame (Eucleia), praise/applause (Eupheme), prosperity (Euthemia), and friendliness/welcome (Philophroysne). Different sources disagree as to the mother of the Charites, but she is often said to have been an Oceanid or Naiad - an attendant spirit of a body of water - emphasising a connection to the natural world. Could Fluttershy be the earthly incarnation of one of these figures? Perhaps the original idea of the Elements of Harmony having a physical manifestation comes from the Greek (and, in this theory, Ancient Equestrian) fondness for personifying abstract traits? There are other minor deities with similar attributes, such as Erea (Latin Clementia), goddess of mercy and compassion.
Although Greek mythology is full of people and deities being turned into trees, I do not recall any such myths connected with the Charites, although it is not unlikely that they would have had trees/groves dedicated to them.
They were also connected with the mysterious Eleusinian mysteries, which were based on an ancient agrarian cult and seem to have featured the idea of resurrection after death. Their rites supposedly took the form of a ritual descent and ascension from the underworld, during which mysterious knowledge was obtained. An Equestrian religious philosopher might see this pattern in the life and times of Fluttershy: a pony born in the cloud-based sky world of the pegasi, she did not attain to a true knowledge of herself and her powers until she descended to earth. She re-entered the world above enriched by her newfound knowledge.
The Elements of Harmony clearly have some religious significance to ponies, but is this because they genuinely have mystical powers provided by some mysterious deity, or is it due to an organised religion which has decided on and preached the concept? The Old English word kyndnes meant 'nation' or 'produce, increase', and the origins of the word kind lie in words referring to types or groups of beings (as in mankind, ponykind). Kindness is not merely a personal virtue but also a social one, and deifying it - as well as encouraging the concept of friendship as a type of divine magic - would ensure peace and prosperity among ponies. But could this be at the expense of other races or 'kinds'? Or at the expense of ponies who don't 'fit' into the accepted social structure and are therefore not the right 'kind'?
There is no way of knowing when the concept of reincarnation entered into the Equestrian consciousness, and whether it has any basis in fact. If Ancient Equestrian religion was analogous with Ancient Greek religion, then it is unlikely that reincarnation initially had any role in Equestrian thought. Nor, in fact, is it native to Hebrew or Christian thought, which regard 'life after death' as a very different thing from reincarnation. Perhaps it was borrowed from another culture. Thus we come to the question, are Tree Hugger's beliefs widely shared? Do they have any basis in fact?
Continuing the Greek theme, 'angel' initially comes from a Greek word meaning 'messenger', and only acquired its religious connotation after contact with Christianity. It was used in Greek translations of
the Old Testament to replace the Hebrew word mal’akh, which was used to refer to any messenger, divine or earthly: only in the Latin Vulgate did the word angelus come to be used exclusively for celestial beings. If Christianity has never occurred in Equestria, then Fluttershy perhaps named her pet Angel due to his communicative abilities (he's very adept at telling her what he wants).
Fluttershy has often seemed like a pony who was born in the wrong element: in the air instead of on the ground. She may have become an Element of Harmony, and thus in some way a religious leader; however, it has not cured her natural shyness and social awkwardness. Perhaps to Fluttershy the consciousness of being a sentient creature is something of a torture; loving nature as she does, the life of a tree perhaps seems quieter. To be at one with nature, rather than to have to navigate the social construct of enforced friendship which seems to play such a role in Equestrian culture and society. If Tree Hugger is simply a very empathic pony - perhaps with a less 'mainstream' mindset than most ponies - then it is likely that she has recognised this trait in Fluttershy, and it may be the origins of their friendship. Perhaps they have spent time meditating in the forest, standing as still as trees themselves.
It need hardly be said that I did not take this seriously and did not intend to step on anyone's religious beliefs in my talk of theoretical Equestrian religious thought. Etymology and comparative religion are both hobbies of mine.
Mana Minori, I love your crazy topics, don't ever change!
Post Merge: December 10, 2020, 04:34:42 AM
Wait, I have more thoughts about this. Ponies speak English, which implies they must have had some (pony equivalent of) Norse or Saxon influences in the past.
Fluttershy in the context of Saxon paganism. Spoiler for length.
Spoiler
While the majority of ponies have very 'English' names, usually with Old English origins, ponies of what might be considered the ruling class (unicorns, inhabitants of Canterlot) often have either Latin names or names which come from either Latinate/Romance or Greek languages (Celestia, Luna, Cadence, Léon, Lyra, Octavia, Lyrica, Fleur de Lis). In real world history, the Romans basically assimilated Ancient Greek culture, thus introducing Greek words, religions and concepts to the rest of the world as they conquered it. So what if what is now Equestria was originally a Norse/Saxon type culture, but was then invaded by a race who brought Greek/Roman influences? This would be supported by the fact that Ancient Ponish has a runic appearance (I think? I haven't watched FiM in forever).
This has some relevance to Fluttershy being or wanting to be a tree. The Norse gods are said to have made humans (or in this case ponies) from driftwood, and the first man and woman were named Ash and Elm. There is also of course Yggdrasil, the World-Tree. Norse mythology also features many dangerous dragon-like creatures.
The conquering race has no doubt assimilated the native religion into their own (already amalgamated) religion, with Yggdrasil perhaps being reinvented as the Tree of Harmony. Perhaps Fluttershy follows a more ancient religion than her friends (who seem to ascribe more to the 'state religion'). She has obviously travelled widely (e.g. while seeing the Parasprites home). Perhaps she came into contact with a Norse-inspired nature-worshipping religion. I could imagine her as a devotee of something like Seax-Wicca. The definitive guide to Seax-Wicca is even called 'The Tree'! If Fluttershy lived in our world, she would absolutely be into it. I also think the god Baldr - good, compassionate, full of the light of purity - would appeal to her. I'm no expert on Saex-Wicca in particular, but Wiccan teachings in general don't rule out a previous life. It's entirely possible that Fluttershy and Tree Hugger genuinely believe in past lives, and believe that Fluttershy was a tree in one of them.