When not reading the manual just take a general approach. Heavy big weapons - strength, quick small weapons - finesse, magic spells - intelligence.
It's quite obvious, that weapon damage scales with appropriate attribute. But my question was about spells. Do ALL spells scale with intellegence? I think that Warfare spells scales with strength and Scoundrel spells scales with finesse, not sure about others, espicially about Necromancer's.