Yeah, yeah, I know!
I was not saying that people mistake year/month/day/hour-old lingering body heat for ghosts! I used heat as an EXAMPLE, because when I said people believing they have encountered ghosts may be really sensing lingering energy and mistaking it as a soul, you suggested two things: that energy does not linger and that we cannot sense it. So I used heat and static electricity as examples of energy that DOES linger and can be sensed, or that simply can be sensed (in the case of static electricty).
My main point: There is stuff out there that the average human being does not understand. If one encounters something they don't understand or don't expect, they will generally try to explain it in any way that they can. Therefore people might mistake general natural phenomonen for ghosts. It doesn't mean they sensed a ghost, but it also does not mean that they are just crazy and making things up.
I can feel a draft and think it is a ghost and be wrong, but being wrong about the ghost does not mean that the draft does not exist. I think instead of trying to look at ghost stories and other things from a deconstructionist point of view (by trying to prove why ghosts don't exist, can't exist, etc), we should instead try to explain what people REALLY sensed. In some cases it may be nothing-- It might be a good story that they made up because it is just that; a good story. It might be someone simply seeing things because they are tired, or seeing things because they WANT to see things (ever go to a location that is supposed to be haunted in hopes of seeing something? Ever think you might have seen something... even if you don't REALLY believe in ghosts?)
Whether entering part of a room that is drafty, somehow sensing the "piezoelectric effects of quartzite", getting shocked by static electricity, or feeling body heat in a chair, people are easily deceived, and if they are not expecting something or don't take the time to look at other possibilities, they may just write the experience off as "ghosts".
As for auras... yeah, we have energy around us. It is not important. It just isn't... people just like to talk about auras because they sound metaphysical and interesting, but they are probably just a mixture of body heat and static electricity. As for aura cameras, I'm not sure how they work but I KNOW that they are not normal cameras... I think they do take pictures of heat... kind of like in the science museum here in town kids can get in front of these big cameras and dance around and see their thermal pictures moving with them, and I know from seeing that that we are all different heats... though under roughly the same, of course. That kind of thing is amusing, but pointless. What can you do with that? Hang it on your wall and say "Oh look, it's my thermal picture/aura photograph?"
However, whether auras are important or are associated with all the stuff metaphysical people say they are associated with (healing, for example)...or NOT... there is still SOMETHING around the body, and some people might call it an aura and assign all kinds of attributes to it. The attributes might be incorrect, but that SOMETHING still exists.