In Pathfinder can spells target invisible opponents?

Question

In the game I was running last night the bad guy cast invisibility on herself. The players managed to work out which 5' square she was in and among other things one of the players tried to use the spell Command to command her to approach.

I made an on-the-spot ruling to allow it (she made the save anyway) but I couldn't find anything in the rules to say definitely whether:

1. The spell works as usual
2. The spell works but has a 50% miss chance as per an attack
3. The spell fails

If it was an AoE spell that would be simple (the spell works).

If it was a ranged touch or touch spell that would be simple (50% miss chance).

But the range is close and the target is one living creature. Does not being able to see the creature despite knowing roughly where it is prevent spell casting on them entirely?

Answer 1

From the Magic section

Some spells have a target or targets. You cast these spells on creatures or objects, as defined by the spell itself. You must be able to see or touch the target, and you must specifically choose that target. You do not have to select your target until you finish casting the spell.

You cannot see the target therefore they cannot be targeted by the spell using sight. If the player was within 5 feet, they could try to touch the target.

To explain why this touch will cause an AOO and why normal touch spells do not provoke attacks of opportunity:

Touch Attacks: Touching an opponent with a touch spell is considered to be an armed attack and therefore does not provoke attacks of opportunity.

The spell in question is not a touch spell, so you are not normally considered to be armed (Unless you have a natural weapon or improved unarmed strike)

Although, if it was just normal invisibility, actually taking that AOO would break the spell, which is also useful.

Answer 2

PFSRD:

Target or Targets: Some spells have a target or targets. You cast these spells on creatures or objects, as defined by the spell itself. You must be able to see or touch the target, and you must specifically choose that target. You do not have to select your target until you finish casting the spell.

By this rule, if you can't see the target, you must touch the target to be able to target them, even if the spell you are casting does not normally require touch. You can target them, just only by touch. (A better option in this case is typically to use area spells if possible.)

This came up in a game I was observing last weekend, only there it was that the caster had been blinded and couldn't remove the condition mid-combat, so was targeting his spells via touch (after we looked the rules up).

Answer 3

Some spells have a target or targets. You cast these spells on creatures or objects, as defined by the spell itself. You must be able to see or touch the target, and you must specifically choose that target.

From Magic section of SRD. So unless your caster was able to actually touch opponent, he couldn't target his spell properly.

Answer 4

From the magic section:

Target or Targets: Some spells have a target or targets. You cast these spells on creatures or objects, as defined by the spell itself. You must be able to see or touch the target, and you must specifically choose that target. You do not have to select your target until you finish casting the spell.

From the Invisibility condition:

The ability to move about unseen is not foolproof. While they can't be seen, invisible creatures can be heard, smelled, or felt.

So I would rule that they cannot be targetted.