So, magic is psychic, like the force. What exactly do we buy a spell for, the rights to realize it?
Thats what I'm wondering.
I much rather prefer the D&D method to the "think, it happens" style of spellcasting (though Dragon age did this decently).
In the D&D method, pretty much damn near anything can happen with magic... You just need to know the spell, and have the ability to hold it if need be. The difference between the right vowel and the wrong one could mean you'd cast a completely different spell. Imagine trying to cast a fireball, but instead you pronounce it "uh" instead of "ah" and you set your crotch on fire. Or you make the somatic motion with one finger instead of two, you might change your hair color.
But, there is a limit to that. The strength of the caster relates to how powerful the spell is. In the mage-fair, they would compete to see who could make a bigger fireball (using the same spell)
And why, if there is no limit, and is psychic, would we need a grimoire in DF (arguably the most RP heavy of the TES games)?
Or a simpler explanation would be that its up to the player to decide.
P.S. Figured out how the whole "two spells cast at once" would work. In D&D, a spell would be memorized/prepared then cast with a command word. You could cast more than one spell if you used the same command word for both. Image how awesome it would be to cast a mirror image spell
and an ignite spell on an arrow that you shot.