But that runs up against the assumption that two solid objects cannot occupy the same space at the same time, and I think the visual evidence of the tree stump outweighs the auditory evidence of the cloak-wearer.
By the same token, invisibility runs up against the assumption that light cannot pass through a solid object without reflecting or refracting. You're telling me that a guard's powers of detection are stumped against the
cloak of elvenkind by one physical assumption, but that against invisibility he is quite willing to discard another, very similar physical assumption. This guard's faith in regular natural laws and his understanding of magic's ability to override them seem very arbitrary.
Furthermore, when visual and auditory evidence are inconsistent, a person tends to get confused and want to investigate further. If
*clang clang clang* "Hmm, all I see there is a stump" leads to "Oh well, I must just be hearing things, no need to get alarmed", then
*clang clang clang* "Hmm, all I see there is thin air" should as well.
But it is how hiding works in 5e. You don't need to see a creature to know its precise location. You can locate it with hearing or some other sense, or even by noticing signs of its passage.
You are arguing that the rules make it just as easy for one human being to locate another without their eyes as with. You are now acknowledging that this differs from reality, in which eyes are a pretty important component of our sensorium and when we can't use them, finding stuff becomes much harder. But you are still
defending these rules. Why? If what you say is true, isn't this a big problem?
"Invisibilty" doesn't need to be understood as such for someone to conclude that someone is there without visual evidence. If visual evidence is required, however, advice was given in AD&D to describe signs of a detected invisible creature as a shimmering in the air, showing the creature's location.
Nor does the
cloak of elvenkind need to be understood as such for someone to conclude that someone is there without visual evidence. And if visual evidence is required, signs might include a corner fluttering or the colors shifting, showing the creature's location.