Thanks for that. I thought it was tied in with the spellcasting, but couldn't find a description of spellcasting in the skills chapter.
That's because the Spellcasting skill is in Chapter 3, ~ pg. 112, near where its associated rules matter
Wisdom score, not bonus? That's a lot of spells for a beginning mage. Though it does say that the first level caster can cast only the zero level spell he/she knows.
On the flipside, the initial spells learned become a map of what the mage can cast later - the spells a sorcerer can cast are tied to his Circle of Power class ability, and after he gets that initial batch he only learns spells from gaining feats, adventure rewards, or each time he permanently increases his Spellcasting ranks or Wisdom score.
Does a caster learn each individual spell, or all related spells. Could a caster who knows Brawn IV not know Brawn I, II, and III? or mass Brawn I?
A mage does not have to know previous spells in a chain to cast later versions.