Lets say you have a Pathfinder Savant and with the 2nd level ability, Estoric Magic, you take the spell "Summon Eidolon". How does that work?
Well, if you don't have an eidolon, there's nothing to summon. So... it doesn't work.
That was my opinion as well, are there any other spells out there that wouldn't make sense, but do work, or don't for that matter?