The Mechanics of Spell Casting

[JMadFour]

Can someone explain this to me?

Lore-wise, how does each Class cast their spells?

[Enkidoh]

Well, the FFXIV website basically mentions how spells are generated in the description of each Disciple of Magic, found here:

Conjurer

Conjury calls upon the elements of earth, wind, and water and concentrates them to a potency at which spells can be weaved. Through practiced meditation on the essences of creation, conjurers draw forth and absorb aether from their immediate surroundings. A wand or cane made from unworked wood is then utilized to focus the aether until it manifests as the desired spell. Versed also in magicks that restore and strengthen, conjurers are regarded as accomplished healers.

Thaumaturge

In the hands of a skilled practitioner, thaumaturgy can be a force of terrifying destruction. At the heart of this school of magic lies the ability to call forth and command the latent aether within oneself through deep introspection.
To then mold that aether into sorcery, the thaumaturge makes use of a scepter or staff, within which is housed a medium—a natural stone imbued with magical properties. Thus armed, the thaumaturge is capable of wreaking considerable havoc via ruinous spells and curses.

Arcanist

Adepts of the art of arcanum derive their might from symbols of power born of geometric techniques hailing from across the southern seas. Held within occult grimoires, these symbols lend shape to the arcanist's aether, thereby allowing him to produce myriad powerful spells.
Using the selfsame symbols to unlock the latent power contained within gemstones, arcanists are also able to summon forth the familiar known as Carbuncle to carry out their bidding.

So from that, basically it can be seen that:
CNJs use a wooden staff to borrow aether from the surrounding environment and to focus it into a spell
THMs use the aether from their own bodies and channels it through their bone or metal staff into a spell
ACNs use obscure mathematics to manipulate aether into whatever form or shape they desire (specifically into the metaphysical entity Carbuncle).

Hopefully that hasn't been too confusing.

[Raezaiel]

The conjurer quest line explains it pretty well. I haven't even got a level 1 BLM or ARC to say whether theirs has any but basically the conjurer calls upon nature's energy and redirects it. There is a girl who refuses to do this but can still cast spell using her own life force. Bad things happen I don't want to spoil it but conjurers merely need the will to use but use the energy from nature basically. Much like cars. Don't run cars on lifeforce.

[Nahara]

The conjurer quest line explains it pretty well. I haven't even got a level 1 BLM or ARC to say whether theirs has any but basically the conjurer calls upon nature's energy and redirects it. There is a girl who refuses to do this but can still cast spell using her own life force. Bad things happen I don't want to spoil it but conjurers merely need the will to use but use the energy from nature basically. Much like cars. Don't run cars on lifeforce.

There's also the fact that Conjurers have to be very careful with the magic that they wield. Unlike the other two forms of magic, conjury draws it's power directly from nature, and it was essentially the reckless misuse of this fact that lead to an umbral era. Using this magic too much essentially began to bleed the planet dry of it's natural life-force. Think of it like what happened to the world in FFVII when Shinra started turning Mako, the lifeblood of the planet, into electricity ("A Mako reactor outside of Midgar usually means there's nothing else out there").

[Enkidoh]

Actually, it wasn't Conjury itself that caused the Sixth Umbral Era, it was the misuse of white magic, a completely different, though partially related, school of magic. Conjury as you said involves borrowing the aether from the environment and then concentrating it into the desired spell. White Magic, on the other hand, isn't given much explanation as to how it's generated, only that it's 'the divine art of succor' (that is, relief/healing), and that people corrupted it, thus necessitating it's outlawing. This seems to suggest that a WHM's power actually comes from a higher power than just the land around them like CNJ does, which would probably be another reason why the Job was forbidden.

As for Sylphie,

the whole reason for her situation was that she was actually very weak in Conjury, simply because she refused to concentrate on the 'whisperings' of the elementals which allow a CNJ to use the aether around them - hence she relied on what was effectively a form of Thaumaturgy where she used her own life force (ala, the aether within her), to power her healing spells (ironically this power was very similar to a traditional WHM ability in past FF games, variously called 'Sacrifice' or, as it was called in FFXI, 'Martyr'). Naturally this began to take it's toll on her, to the point when she discovered how to cast Raise, it led to a potentially dangerous possibility that if she ever cast it, it would actually kill her because it would restore someone to life at the cost of her own. Luckily though she soon overcomes her own stubbornness and is revealed to be a potent CNJ in her own right (no thanks to the player), finally opening her mind to the elementals and thus was then able to conjure spells properly.

So basically this shows, that for CNJ at least, they have to let go of stubbornness and arrogance to clear their mind and focus on their environment, in order to hear the elementals, and hence be able to actually cast spells.

[Urthdigger]

As I recall from the related quests, Black Magic and White Magic came about at roughly the same time (Black magic coming first and white being a countermeasure as I recall). Both of them drain the aether from the surrounding environment, and extensive use of both happened during the war of the magi, causing the umbral era. This led to them both being outlawed. This does bring up an interesting detail, that white and black magic are not very different. My guess is that the way they work is a bit of a combination of the two. Like conjury, it uses the aether of the surroundings more than the individual, but like thaumaturgy there's more control over it: You're not beseeching the land for aid, you're taking it.

[JeniLinsky]

If you watch the animations for the spells, you can see the aether drawing into the focus (my sword, as a paladin, which is interesting for being in no way natural) and then the caster physically hurls the aether out, letting it assume its spell form as it flies.

[Wolfandre]

If you watch the animations for the spells, you can see the aether drawing into the focus (my sword, as a paladin, which is interesting for being in no way natural) and then the caster physically hurls the aether out, letting it assume its spell form as it flies.

It could be that one doesn't really need a focus to use magic, it just helps (stat bonuses). Therefore, really anything could be used to focus it, including man-made weapons.

So, in a way, the Armoury system doesn't really do much of anything for our spellcasting other than allow us to mechanically access our spells in the game.

[Nahara]

It could be that one doesn't really need a focus to use magic, it just helps (stat bonuses). Therefore, really anything could be used to focus it, including man-made weapons.

I've actually thought about this quite a bit. My end conclusion is that you need a focus in order to cast most of your spells. Think about the spells you get access to through cross-class abilities and they're actually pretty simple stuff: Cure, Aero, Protect, Blizzard II, Ruin. These are spells that could be dirt simple and easy to pull off without any kind of special focus. However, if you wanted to cast the more complex or powerful spells like Shadowflare, Medica II, and Thunder III, then you need a legitimate focus. And if you wanted to cast some really powerful spells, like Tri-Disaster, Sacred Soil, Holy, and Flare you'd need the power and knowledge granted by soul crystals, on top of the normal focus.

[Wolfandre]

I've actually thought about this quite a bit. My end conclusion is that you need a focus in order to cast most of your spells. Think about the spells you get access to through cross-class abilities and they're actually pretty simple stuff: Cure, Aero, Protect, Blizzard II, Ruin. These are spells that could be dirt simple and easy to pull off without any kind of special focus. However, if you wanted to cast the more complex or powerful spells like Shadowflare, Medica II, and Thunder III, then you need a legitimate focus. And if you wanted to cast some really powerful spells, like Tri-Disaster, Sacred Soil, Holy, and Flare you'd need the power and knowledge granted by soul crystals, on top of the normal focus.

I'll agree to that, in a way. I'd say it's more of a personal focus than a material one. If I'm focusing on thaumaturgy, an aetherial sport, maybe I can remember how to strike without garnering attention, but not the more complex stuff like poisoning the tip of my weapon. However, if I were practicing my martial abilities with a sword and shield, I might be able to apply that poison somewhere, but not have the aetherial state of mind to litter the area around me in frost.

However, I just think that Soul Stones are cheating. Have one of those in hand and you have a bit of power from every previous owner. I imagine the older they are, the more powerful you get, which is why they are often heavily sought after in the job quests. But that's not even your power or your experiences, it's other summoners, paladins, etc. That may be also why we cannot use as many actions from other classes; our brains are too addled with knowledge that isn't ours to remember everything we know and apply it to battle.