I think these two terms are a good example of how some of the gaming terms have gone overboard and go against common sense and the general usage of a language. Here are some examples. From Unseen: "If a creature is unseen, you have no idea where it is." Ok, but that's not what unseen means. Unseen in common usage just means "not visible." If a creature is standing in a puddle or leaves some visible trace than it could still be not visible yet I would know where it is. Unseen and unaware something is there are not linked in any logical way. This might be a quibble, so here is a stronger example. From Invisible: "If the creature becomes invisible while seen by you, it starts out sensed, since you know where it was when it became invisible, though it can
proceed to Sneak after becoming invisible to become unseen." Here we have two problems: logically, invisible and unseen are the same thing in everyday usage, and to say something invisible can be "un-unseen" and then use Sneak to become "re-unseen" is ridiculous; second, it's creating a tier where unseen is a higher boon than sensed, where they are not mutually exclusive. If seeing is your only method of detection, then a creature can be sensed (through smell, hearing, or some other giveaway of its location) while still being unseen (in common usage). And if you have other senses, being unseen isn't even that big of a deterrent. Many animals have senses much more accurate than sight, a fact which is even called out in the "detecting with other senses" sidebar. Instead of hanging a lamppost on how bad this terminology is, I think these terms should be changed to be more accurate and better conform to everyday language. I think "detected" and "undetected" would be much better than "seen" and "unseen," for example.
