Thanee said:
So, there you have the list of things,
True Seeing does
not. Also no listing of HiPS. So it neither
does nor
does not see through the ability according to the spell description.
Your logic appears to be faulty. No spell, in all of D&D, with the exception of Wish and Miracle, is open-ended. If the spell doesn't say it does something, it doesn't do it. If a spell says, "This spell causes X to occur", then that's ALL it does. Even if it provides a list of things that the spell does NOT do, that by no means say that it does everything except those in the list. True Seeing, for example, provides no clause saying, "True seeing does not cause a fireball to appear in front of the caster." Therefore, by your own apparent logic, a DM could rule that it DOES cause a fireball to appear in front of the caster, simply because it isn't included in the list of things it DOESN'T do. My point is that it provides a strict list of things it DOES do, and Hide in Plain Sight by no means qualifies as any of those. Even if it isn't included in the list of things that it DOESN'T do, that means nothing- as there's an infinite number of things not included on such a list. The spell description doesn't say it penetrates Hide in Plain Sight, and therefore, it doesn't.
Thanee said:
True Seeing gives you the ability to see all things as they actually are.
Completely and totally flavor text. Game-mechanic-wise, it does not do that at all. True Seeing does not let you see things as they actually are. If a man is wearing a mundane disguise to look like a woman, the spell simply tells you there's a woman standing in front of you. The person, however, is actually a man. Why didn't True Seeing show that man as what he really was, if that's what the spell claims to do? Not only that, but you'll note that True Seeing sees through even non-magical darkness. How is that showing you things as they actually are? It's actually dark- but the spell still penetrates it. (In fact, before they introduced that feature in 3.5, my DM would always say, "Okay, you cast True Seeing. It's Truly Dark.") Therefore, that line of flavor text has no place in this discussion.
Thanee said:
To me, there is only one reasonable conclusion, that True Seeing allows to see someone hiding in plain sight. Because there is nothing hindering the spell from working at all.
Except that nowhere does it say that True Seeing does that. If you're taking True Seeing as an open-ended spell, telling yourself "True Seeing does everything except what's listed in this description", then you're going to believe that no matter what- but it's a faulty line of logic. There's nothing hindering the spell, of course- but there's nothing compelling it either. If nothing gets it going, nothing needs to stop it.