So I have a psychic in PFS who took the Focused Force amplification for some reason (it's been a while since I picked it) and I've been going over what he actually can and cannot use it on.
Magic Missile - obviously, since it's a direct damage spell that has damage dice.
Spiritual Weapon - well, it creates a weapon made of force that has a set damage die rather than a direct damage spell, so we get into "maybe" territory here.
Force Sword - this is where the problems begin, since this spell creates a +1 longsword made of force that you can hand to others.
I tossed this question onto a PFS-specific IRC channel, and got both the response "I'd allow it to work on all of those" and "I'd allow it on Spiritual Weapon, but not Force Sword".
Is there an official ruling on how this amplification affects spells like this that don't do direct damage, but rather create effects that do damage?
Focused Force (Su): When casting a force spell, the psychic can increase the spell's damage by spending 1 point from her phrenic pool. Increase the die size for the spell's damage by one step (from 1d4 to 1d6, 1d6 to 1d8, 1d8 to 1d10, or 1d10 to 1d12). This increases the size of each die rolled, so a spell that dealt 4d6+3 points of force damage would deal 4d8+3 points of force damage instead. This amplification can be linked only to spells that deal force damage, and only if that damage includes a die value. A spell that already uses d12s for damage can't be amplified in this way.
While Magic Missile and Spiritual Weapon both deal force damage, Force Sword does not; while the weapon is made of force, it deals damage as a longsword. In other words, it deals slashing damage, not force, and therefore isn't compatible with the amplification.
This amplification can be linked only to spells that deal force damage, and only if that damage includes a die value. A spell that already uses d12s for damage can't be amplified in this way.
That seems pretty clear. Magic Missile and Spiritual Weapon both deal force damage.
Force Sword... hmm. Yeah no. It's hardly clear, but it creates the weapon, that you then wield. It's dealing slashing damage, not force damage. Being a force effect, it would do full to incorporeal, but it doesn't actually deal force damage. Spiritual weapon specifically calls out that it damages as a spell (and thus doesn't have to deal with damage reduction). Force Sword would deal damage as a longsword would.
Sorry it wasn't the answer you hoped for.
Edit: Completely ninja'd - nice succinct answer Saethori.
P.S. You may want to reference what books these options are from - took a bit to locate.
I'm not looking for any specific answer here - just one I can see the logic behind, which I can see in regards to Force Sword. However, if someone wanted to be super pedantic, couldn't they state the amplification doesn't work on Spiritual Weapon either, since it creates a weapon that deals force damage instead of dealing force damage directly? (To this, my response would be "but it's an evocation, not a conjuration".)
And I figured since this is an online forum, people would just use a search engine to find the spells.
However, if someone wanted to be super pedantic, couldn't they state the amplification doesn't work on Spiritual Weapon either, since it creates a weapon that deals force damage instead of dealing force damage directly?
It strikes as a spell, not as a weapon, so for example, it can damage creatures that have damage reduction.
Their pedantry wouldn't have much to stand on.