So here's the set-up: I'm playing an Aasimar with a variant set of racial abilities, which happen to include in my case Detect Thoughts as a spell-like ability. As such, it has no verbal or somatic components, so I can activate it mentally. The question: If, without giving any outward sign, I activate it while in conversation with someone and keep it trained on that person for 3 rounds, such that the person then gets a Will save to avoid having his surface thoughts read, would the person know that his thoughts were being probed? Would he know whether or not he made his save? Only if he made his save? Not even then?
Fwiw, my inclination is to say the subject certainly shouldn't know his thoughts are being detected before the 3rd round; otherwise the traditional use of the spell to find out whether the room behind a door is occupied would alert the occupants to the presence of someone, which would remove much of the point of using the spell. But I also tend to think a subject wouldn't know its thoughts were being read if it failed the save, since otherwise, if it did realize that, it might try to change the content of its thoughts, and that doesn't seem fair. The hard case, to my mind, is the case where someone makes the save and resist having their thoughts read. In that case, I can imagine saying that the subject knows something's going on and feels mentally invaded, though he might not be able to pinpoint the invader. But I can also imagine ruling that this is purely a passive effect and leaves no trace, even when the spell is resisted. And this matters, since I might try to read the thoughts of someone I don't want to make an enemy, and if there's a chance my attempt will be detected, I run the risk of pissing that person off.
In any case, I'd like other people's thoughts about this! Please make them detectable! :-)
I recall a rule (which at present I prove unable to find, so it may be a 3/3.5 reminiscence, although I was fairly sure to have seen it in Pathfinder too) that when someone it affected by something that requires a Will save, regardless of the result they are aware that something tried to mess with their mind (of course, by this thing alone, they have no means to know what or who exactly tried to affect them).
In other words, they are just set on suspicion.
If your GM chooses to use this even in the case that it really has not been brought into Pathfinder, bear in mind that obviously it won't apply to some situations (like an unconscious target, or a charmed one).
So here's the set-up: I'm playing an Aasimar with a variant set of racial abilities, which happen to include in my case Detect Thoughts as a spell-like ability. As such, it has no verbal or somatic components, so I can activate it mentally. The question: If, without giving any outward sign, I activate it while in conversation with someone and keep it trained on that person for 3 rounds, such that the person then gets a Will save to avoid having his surface thoughts read, would the person know that his thoughts were being probed? Would he know whether or not he made his save? Only if he made his save? Not even then?Fwiw, my inclination is to say the subject certainly shouldn't know his thoughts are being detected before the 3rd round; otherwise the traditional use of the spell to find out whether the room behind a door is occupied would alert the occupants to the presence of someone, which would remove much of the point of using the spell. But I also tend to think a subject wouldn't know its thoughts were being read if it failed the save, since otherwise, if it did realize that, it might try to change the content of its thoughts, and that doesn't seem fair. The hard case, to my mind, is the case where someone makes the save and resist having their thoughts read. In that case, I can imagine saying that the subject knows something's going on and feels mentally invaded, though he might not be able to pinpoint the invader. But I can also imagine ruling that this is purely a passive effect and leaves no trace, even when the spell is resisted. And this matters, since I might try to read the thoughts of someone I don't want to make an enemy, and if there's a chance my attempt will be detected, I run the risk of pissing that person off.
In any case, I'd like other people's thoughts about this! Please make them detectable! :-)
If your spell is not saved against, then no they have no idea. If it is, then they have a clue because they feel a hostile tingle. Here is the relevant text.
Usually a harmful spell allows a target to make a saving throw to avoid some or all of the effect. The saving throw entry in a spell description defines which type of saving throw the spell allows and describes how saving throws against the spell work.
Negates: The spell has no effect on a subject that makes a successful saving throw.
Partial: The spell has an effect on its subject. A successful saving throw means that some lesser effect occurs.
Half: The spell deals damage, and a successful saving throw halves the damage taken (round down).
None: No saving throw is allowed.
Disbelief: A successful save lets the subject ignore the spell's effect.
(object): The spell can be cast on objects, which receive saving throws only if they are magical or if they are attended (held, worn, grasped, or the like) by a creature resisting the spell, in which case the object uses the creature's saving throw bonus unless its own bonus is greater. This notation does not mean that a spell can be cast only on objects. Some spells of this sort can be cast on creatures or objects. A magic item's saving throw bonuses are each equal to 2 + 1/2 the item's caster level.
(harmless): The spell is usually beneficial, not harmful, but a targeted creature can attempt a saving throw if it desires.
Saving Throw Difficulty Class: A saving throw against your spell has a DC of 10 + the level of the spell + your bonus for the relevant ability (Intelligence for a wizard, Charisma for a bard, paladin, or sorcerer, or Wisdom for a cleric, druid, or ranger). A spell's level can vary depending on your class. Always use the spell level applicable to your class.
Succeeding on a Saving Throw: A creature that successfully saves against a spell that has no obvious physical effects feels a hostile force or a tingle, but cannot deduce the exact nature of the attack. Likewise, if a creature's saving throw succeeds against a targeted spell, you sense that the spell has failed. You do not sense when creatures succeed on saves against effect and area spells.
Automatic Failures and Successes: A natural 1 (the d20 comes up 1) on a saving throw is always a failure, and the spell may cause damage to exposed items (see Items Surviving after a Saving Throw, below). A natural 20 (the d20 comes up 20) is always a success.
Voluntarily Giving up a Saving Throw: A creature can voluntarily forego a saving throw and willingly accept a spell's result. Even a character with a special resistance to magic can suppress this quality.