[Nerull]

I may be wrong, but here goes...

I thought that intelligence only has to do with actually learning mage spells (and dual-class requirements, of course). If I remember right, it has no effect on the number of spells per level (determined by level, per the chart in the back of the manual) or on the actual level of spell that you can cast. This is different than the pnp game, where intelligence does stop you from using certain level spells. The reason I say this is that I just finished the game with Aerie in the party, and she was casting 9th level mage spells just fine with a 16 intelligence. When it came time to learn the spells, then I had to use the potions of genius, since it was the only way to both expand the number of spells per level that she could scribe and the level of spells she could scribe. But once the spells were in her book, intelligence had NO effect whatsoever on her actual spell use.