Felix said:
Ok, so what are surface thoughts?
Inner Dialogue type stuff, whatever you are actively concentrating on right now. Stuff like "I have to get to work quickly or I'm going to be late". As opposed to sub-surface thoughts or memories.
Can you send false surface thoughts?
I see no reason why not. Of course that usually assumes the person is aware their mind is being read and is trying to decieve the mind-reader. In which case the trick would be to think a false thought without first thinking about the fact that you are going to lie or what that lie would be, an instinctive lie.
Then again a person may simply be daydreaming or imagining something false in which case there would be no way to tell. I remember an excellent Twilight Zone eipsode where a guy who works in a bank suddenly develops the ability to read surface thoughts. After messing around with the ability all day he happens to read the mind of the elderly bank guard who is thinking about robbing the bank that night and running off to a tropical retirement so the teller raises a big panic about it only to find that nothing happens. Later the guard confronts him and asks him about the mess and confesses that robbing the bank has always been his secret daydream for more than thirty years but he never told anyone. Great eipsode.
Can people detect if they are false surface thoughts?
Just off the top of my head, I would say that if you are actively trying to think false thoughts (as opposed to daydreaming, see above) that you would have to make a check to skip over the "I'm going to think a like now" part of thinking. I would allow a Bluff check at -10 on the theory that a really good lier can instinctevly whip out a lie. I would also allow a Concentration check against DC 30 or so on the theory that it should be possible to control your own thoughts in that manner if well-trained but not something anybody without some experience could ever hope to do.
What are sub-surface thoughts?
Stuff that would be a surface thought except that you aren't thinking it right now. As opposed to memories. Thoughts like "I am not the Duke but an imposter in disguise". Unless the thinker has some reason to think about his situation (perhaps he looks in a mirror to check and see if his disguise is holding up) these thoughts stay in the sub-conscious.
Can you mess around with sub-surface thoughts?
You mean can the spellcaster mess with someone elses sub-surface thoughts? No way, not with this spell.
Are these thoughts part of your conscious or sub-conscious mind?
Sub-conscious
Can a creature who is immune to [Mind-Affecting] spells, meaning he has unbeatable SR against these spells, still be affected by Detect Thoughts because the spell doesn't allow for SR?
I think that the "unbeatable SR" is just a way of illistruating the point that a target having immunity does not prevent a spell from being successfully cast, it just prevents the spell from affecting that target (which may in fact cause the spell to fail, depending on how it is targeted). The way I play it is that if a creature is immune to mind-affects then any spell with the [Mind-Affecting] descriptor has no effect on them.
If you know a doppleganger is reading your mind, how do you screw with him so that he doesn't know every move you're going to make?
See my above answer to knowing weither or not a surface thought is false. If OTOH you know someone is reading your mind and simply want to NOT THINK about a particular secret, as opposed to giving a false lead, so that they do not discover the information then I would make that a DC 15 concentration check, difficult but not unreasonable.
