Hriston
Dungeon Master of Middle-earth (He/him)
But what is happening in the fiction if a person is looking at an elf through the snow, and then - at the gaming table - the player of the elf declares "I hide" and rolls a DEX check and gets a result higher than the observers passive Perception?
I think it is possible that the snow swirls around the elf, making him/her vanish from sight. Another possibility is that, at the behest of the elf, the snow briefly flurries into the eyes of the observer, rendering him/her a non-observer. But then I'm puzzled why it is a DEX check.
Even if it's camouflage - eg the elf's skin changes colour (not something I've ever heard suggested, but at least a logical possibility) - that doesn't explain why it would be a DEX check. (I assume that noone thinks that the elf is applying greasepaint to him-/herself, or rapidly changing clothes, and that that is why it's a DEX check.)
I gather that @Hriston thinks that none of these scenarios is a possibility within the fiction...
That's right. I don't read Mask of the Wild as some limited form of invisibility. It gives the wood elf an additional circumstance in which to hide the same way in which all other characters can hide in a heavily obscured area, i.e. subject to the restriction that she can't hide under circumstances in which her location is known (seen clearly, making noise, etc.).
I've been assuming that ((at least in this discussion, which is about whether or not things are hidden or perceived) by "knowing the location" is meant something along the lines of "knowing in virtue of perceiving", not simply "knowing in the sense of believing because told by someone else who is reliable". There's a whole literature on this (it's modern version begins with the famous 1963 paper by Gettier), and on whether we should call the second sort of thing "knowledge" at all (in a 1912 book that predates the modern iteration of the discussion, Bertrand Russell called the second sort of thing "probable opinion").
Yes, I would draw the same distinction as Russell. While I agree with most of what [MENTION=6788736]Flamestrike[/MENTION] has said in this thread about hiding, I would differ with him or her about the ability of a creature to hide/stay hidden from someone who has been told by someone else where the creature is hiding. I don't believe that having that sort of second-hand information counts as truly knowing the creature's location. It's that the veracity of that information is only probable that makes identifying the creature's location into guesswork, and I would leave it up to the player to decide whether to trust that information or not.
On the other hand, with regard to the situation in which a creature steps behind a pillar or into a box under direct observation such that the observer's sense of object permanence tells the observer that the creature can only be in that exact location, I would regard that as first-hand knowledge of location. The rather improbable possibility that things like teleportation or secret doors are involved need only be taken into consideration if those things are actually present and at work in the situation.
Now, relating this to the current discussion (and I'd be curious to hear @Hriston's views on this - I suspect that, like me and perhaps some others here, Hrisotn is fairly familiar with the AD&D hide in shadows rules): it's one thing to say that an elf who is concealed in a snowstorm is hard for an observer to spot (ie is entitled to make a DEX check to remain hidden although the storm is not heavy enough to conceal ordinary people); it's a different thing to say that an elf who is being observed through a snowstorm can suddenly - by magic, as it were - render him-/herself invisible.
Mask of the Wild doesn't say anything about magic or invisibility. It only presents a situation in which a wood elf can try to hide in which others cannot. Other creatures require a heavily obscured area to hide in. The wood elf can hide (normally) in lightly obscuring natural conditions. Under that interpretation, there is no contradiction between the feature and the hiding rules in general, and no need to invoke magic as an explanation. The title of the feature, however, does offer an explanation for the wood elf's knack for hiding under such conditions. Like a mask, the wood elf is able to "wear" or "put on" elements of the natural world to conceal her position. However, just as a mask is unable to hide the identity of the wearer that is observed donning it (because you already know who she is), "nature itself" cannot hide the location of a wood elf that is first seen unhidden within it.
The name of Naturally Stealthy also offers a clue that there is nothing supernatural about the lightfoot's ability. I don't see any reason why the wood elf's ability should be any different.
I mentioned JRRT's elven cloaks upthread. In the case of these, the wearer doesn't get to choose - the cloak conceals him/her, and then once s/he choose to become visible the jig is up (until the observers look away). I am guessing that this might be how @Hriston envisages the elf's ability working: as soon as it starts snowing the elf becomes hidden (though we may not actually roll the DEX check until later on when we need to know whether or not another can spot him/her). And if the elf subsequently, or nevertheless, comes under observation, then s/he is not hidden to that observer until something happens that makes the observer (even momentarily) lose sight of her. And the mere continuation of snow falling wouldn't be such a "something".
No, this isn't how I envision it working at all. I find the idea absurd that any wood elf that wanders into an area of moderate foliage, for example, or who happens to be caught in a snow storm, suddenly becomes invisible to all onlookers, whether she wills it or not. I almost equally dislike the idea that every wood elf comes fully equipped with a cloak of elven-kind.
No, the way I envision it working is that a wood elf that is lightly obscured by natural elements can be seen clearly by any potential observer, just like any other character. The feature doesn't change this. Also just like any other character, a wood elf can't hide from an observer that sees her clearly. The feature doesn't change that either. What the feature changes is the range of circumstances in which the wood elf can be unseen once hidden. Just as most characters, in my view, would need to be unobserved while getting into position behind a large tree or boulder in order to hide there, a wood elf also needs to be unobserved while donning the "mask of the wild" in order to hide behind it.