"+1 Caster Level" (Cleric domains)

[Pax]

I would say no, as they both come from the same source.

Um, not really. Both come from domains, eys -- but one is the "X domain bonus" and the other is the "Y domain bonus" -- not that the bonus is named.

And that's anotehr key consideration; IIRC, non-named bonusses always stack with each otehr, unless otherwise stated for each such bonus.

As for the application to the Illusionist spells, I'd say no to that also. You are close to your God's province over illusion, and thus have more expertise with the divine powers that he/she grants you. This expertise with divine power would have no effect on the arcane spell casting.

John

This is directly contrary to the spirit, if not the letter, of the rules as presented in teh core books.

What about the Wizard/Cleric who takes "Spell Focus: Illusion" as a wizard bonus feat; does it then apply ONLE to their wizard spells of the illusion school?

I say not. The rules say not.

Let's go further. The "Magic" domain ability in fact especially indicates it does stack with non-cleric levels.

I think, if a cleric serves a deity well-focussed on illusion magics, and is not "only" a cleric but also an actual illusionist, then they are playing closer to the archetype of their deity in several ways. Ergo, they should get the bonus for non-cleric spells, regardless.