Henrix said:You still have to declare a target for your attack.
How would that work?
You walk into a seemingly unoccupied room, cast True Strike, and say "I will shoot the invisible guy I think is in this room" and fire at random?
What?
You walk into a room. You cast True Strike. You attack the invisible guy. It might be your ally. The spell might fizzle if there is nobody in there. The GM might roll randomly if there are 5 invisible guys in there.
You walk into a room. You do not cast True Strike. You attack the corner of the room, hoping to hit an invisible guy there. If one is there, you might hit him.
You walk into a room. You cast Augury about shooting into the corner. Does the Augury automatically not take into account the invisible guy standing there because it cannot perceive him?
Why would Invisibility foil one type of non-sight related divination and not another? Yes, some people think True Strike relies on sight, but it doesn't. It's insight, not sight. Otherwise, it would not automatically work (95% of the time if you do not roll a one on the to hit) against Displacement.
This is magic we are talking about. Magic allows characters to fly and teleport across the world and go to other planes of existence.
You walk into a room. You cast Detect Evil. Does the Detect Evil automatically not work because it cannot perceive the invisible guy standing there?
Why is it so difficult to comprehend that a divination spell can give you insight on where to attack on the next round? You get the urge to fire over by that rock for example.
Also, you can declare an attack against anyone at any time in the game, even if they are not there.
“I fire my arrow up into that tree, hoping to hit any bandits that might be lurking there over the road.”
Are you prevented from doing this just because you do not KNOW that someone is there?
Ditto for True Strike. If you cast it, it will work to the best of its ability. If there are several targets that may be applicable, the GM has the option to either disallow it, or decide for the spell, either randomly or based on some criteria.
But, that does not mean that you cannot make the attempt and that the spell will not try to assist in guiding your aim. If there is only one target available or you have a good idea about your target (i.e. the spell caster that just went invisible), I would imagine that most GMs that interpret True Strike as I do would just let the spell do its work.