My Little Thesis: Understanding Magic

Or my thoughts on how magic and Cutie Marks function.

First off: this is being written primarily to get my thoughts in order about how I think magic in Equestria works, so that when I get around to writing a story I will have this laid out before hand and won't have to deal with it then. Read this or not, it doesn't matter to me though it may give you insight on how the world in whatever stories I end up writing work. Naturally if part of this is necessary to understand any future stories it will be explained in some manner in said story.
Second off: Some of the ideas in this came to me from reading someone's story and taking a shine to a particular piece of their world building. Off the top of my mind changeling magic recharging comes from...um I cant find it anymore. That's awkward. Well if I find it later I will update this with the name. I hope no one minds me nicking a bit of world building.
Now on to the actual content of this. (Probably most of the original stuff in this is in the cutie mark section, so you might want to skip to that. I didn't realize how long this would end up being.)

My basic theory is that all of the pony races as well as most of the other sentients we have seen have in Equestria have an internal reservoir of magic that I will refer to as a mana pool because I have played to many videogames for my own good. This slowly refills its self over time. Both the amount of mana one can hold(Twilight's is HUGE) and how fast it refills vary from pony to pony. Earth Ponies and pegasi(pegasuses(Seriously what is the correct plural? Spell check says Pegasuses but it looks and sounds so weird. I think i will stick with pegasi.)) tend to have larger mana pools and faster recharge rates than unicorns. Mana pools grow with age, but much slower than ponies, allowing the very young to achieve magical effects on themselves they otherwise couldn't(as evidence by Pumpkin and Pound). Recharging mana is faster when at rest and can be increased by eating as the body can covert some calories into mana. But wait you say, unicorns are the ones who cast spells, why don't they have the larger mana pools? Well we have seen Twilight herself, the most magically powerful unicorn in pretty much ever, get tired from spell-casting, but the about the only time we've seen AJ get tired from employing the earth ponies subtle plant based powers was the Applebuck Season incident, and even how long she lasted there was really impressive. And pegasi don't get tired from flying around all day. So thus they have bigger reserves.

This leads nicely into the magic of pegasi and earth ponies. Some of this is kinda self evident from the show itself, but as this is a compilation on my thoughts on how magic works, a decent amount of that is to be expected.

But first: a bit on focuses, active vs passive, and instinctive vs learned because I am going to use these terms rather frequently in the upcoming paragraphs. Active magic, ex, unicorn spells, flight, and earth pony farming is all done through focuses. Mana is channeled through either the hoof, wing or horn to produce the affect. Passive magic is some trait that is always in affect, ex earth pony strength. Instinctive requires no training or thought, ex earth pony farming, but may be improved with practice. Learned is things like unicorn spells. Unicorn spells cast instinctively in reaction to something like teleporting when scared is not instinctive magic, but learned magic used instinctively. Twilight's lack of horn in Equestria Girls lead to her being unable to use magic, as she had no focus. Had she found a way to use an external focus, as Sunset did with the Element of Magic(In her transformation, Sunset turned her hands into foci magically resembling some twisted amalgamation of earth pony hoof and unicorn horn), she would have been able to use spells.

Pegasi should not be able to fly with the wing to body size they have. Period. I don't care if they have hollow bones like birds. No flying. But since they obviously do fly, something must aid them. That something is obviously magic which is focused through their wings. Pegasi magic also lets them do things like walk on clouds and manipulate the weather; both of these focused through the hooves. The cloud walking and flight is an instinctive use of magic, the weather control a well controlled purposeful use. We have additionally seen another aspect of pegasi magic, the leaving behind of contrails during flight, both by Rainbow Dash(rainbow) and members of the Wonderbolts(storm-cloud stuff). This is probably instinctive for Rainbow, but is able to be learned and controlled, as is such for the Wonderbolts, explaining how they all have the same contrail effect. Pegasi magic also provided partial protection from extreme temperatures(idea from multiple fanfics, at least I don't remember it in the show); this is an instinctive use.

Earth Ponies magic is effectively all instinctive. When they work crops their magic is focused through the hooves promoting proper crop growth and health and etc. Similarly some earth ponies can use a similar form of magic to make rocks and crystals grow and/or change(the Pies are prime example(and the only one we have)). Additionally they receive increased stamina(as evidence by Applejack and Pinkie Pie), strength(Big Mac) and longevity(Granny). These are all instinctive passive effects. Additionally earth ponies are capable of, with training, some active effects. A personal favorite idea of mine is standing firm from "It's a Dangerous Business, Going Out Your Door". which is, for those who haven't read that amazing story, a technique that turns an earth pony into an immovable object as long as they are on the ground. This is, like all earth pony active magic, channeled through the hoof.

Unicorn magic is all learned and active. The focus is the horn. Learning spells works much as in Harry Potter or D&D or pretty much any fantasy setting. You learn how to do the spell. You cast the spell. Magic happens. If you are the one who invented the spell, you can probably cast it better and more effectively than anypony else since you probably understand it better. Spells for the most part require as much energy as doing something normally, its going to take about as much out of you lifting something with telekinesis as it would by hoof, but the energy comes from your mana pool, not calories. A distinctly colored aura form around the tip of a unicorns horn during spells casting. For the most part the color is constant for an individual, but some types of magic, most notably illusions and dark magic have a tendency to always take one specific color (green and black respectively)

The cutie mark represents, as we are told and shown in the show, what a pony's special skill is. Additionally cutie marks make magic related to ones special talent more effective: by making it require less mana or by letting the pony put more mana into a magical working, or both. Perhaps more accurately a cutie mark represents what one can do at a discount or is able to put more into. Earth Ponies with cutie marks relating to the growth of a specific crop can put more magic into growing that crop than an earth pony lacking the relevant cutie mark, making their crop better. A unicorn skilled at, say, defensive spells can cast those spells for less mana than a unicorn with a cutie mark for say, offensive spells. Their are some cutie marks that this doesn't work for, such as if a pegasus has a cutie mark for novel writing, there is nothing in what pegasus magic is capable of that the cutie mark can discount or make more effective. In this unicorns are lucky, as their is pretty much always a some sort of spell relevant to something. For an example, we go back to the book writing cutie mark, which would make a dictation spell cheaper. Furthermore the amount of the discount or the amount of mana that can be put into something is related to the specificness of the cutie mark. The more specific the mark, the more effective you are at it. The relations ship is exponential and the discount percentage based. For unicorns the relationship is stronger than that of earth ponies or pegasi, in some cases preventing the unicorn from doing spells outside their area of expertise beyond basic levitation. As an example of effectiveness we go to farming. From most to least effective at say apple farming we have: Earth Pony with apple farming cutie mark, pegasus/unicorn with same mark, earth pony with general farming mark pegasus/unicorn with general farming mark, earth pony with non-farming mark, pegasus/unicorn with non-farming mark, and lastly me cause I cant grow things worth a darn. Twilight's cutie mark is magic, thus granting her a discount on everything, but not a big one on anything, but that doesn't matter much since her mana pool is so large anyway. I will discuss cutie mark symbolism in a latter post, as this one is getting really really long.

Onto other species. Dragons, griffins, and changeling have similar flight magic to pegasi. Dragons also have fire-breath, which is active and learned(quickly and instinctively learned, but learned). Changelings are also capable of unicorn style magic, and all have a high discount on self illusion spells. However they do not recharge mana overtime and cannot convert calories into mana, they can only recharge mana by converting emotion energy into it. Donkeys have the earth pony style innate strength magic to an on average higher degree than an earth pony.

There is of course one pony whose powers don't fit into this analysis. Pinkie Pie. I have no idea how she works, nor will I attempt at analyzing it, because as Twilight taught us, down that path lies madness and men in white vans coming to pick you up when you start foaming at the mouth.

By Celestia's sun and Luna's moon! That was longer than I was expecting. I do hope no one who is actually interested in my ramblings is put off by the length of this.