The whole world is a computer simulation, wizards are hackers spitting out the dev codes. They think they are pretty slick and don't realize what they could do with a run command.
Less silly, the Gods made the world as a song and you can sing bits of it. Learning the whole song is impossible due to the relationship of parts to each other; each word you sing alters the way you have to sing every other part so you can't learn the song without already knowing it. All magic is bits of it; dragons breath and spells are the same thing using different bits. Ghosts are echoes in the song, etc.