Guys - This is only a nightmare, not real.  It is the year 2011 - not 1300! There is no such thing as witches, fairies, magic, ghosts, etc... Invisible people do NOT exist.

All the people that say that they have seen something are mistaken.  Please stop this sillyness by saying that it is true, this is not funny. you will scare poor centrino.  Read and learn something new and be less ignorant.

It is a scientific fact that the brain can play tricks on your mind. UkEngQatar has touched on some very good points in his post above.  For those that might be interested I will take the time to try and explain very briefly a little bit more about how and why this happens below, especially when combined with tiredness/ sleep/ dreams (with or without eyes partially open) etc....

The Brain is a very strange and complex organism.  The best way to think of it is by comparing it to a computer.  The human brain is basically a computer processor receiving inputs from different devices, inputs from your webcam are like your eyes, inputs from the mike are like your ears, the screen is the output (what the computer tells you it saw - Not always the same as what actually happened!), etc...

The problem is this... the inputs we receive at the eye are not exactly what the brain tells us. (same with the ears too, more later on that, if I have time).  The eye is pretty good all round but it has its limitations.  For example if we examine the eye closely we know it is made up of "rods" and "cones".  There are 120 million rods and only 6-7 million cones. the rods are more sensitive but can only see in black and white and the cones see in colour and are in a donut shape around the very centre of the eye's vision.  We can not see colour in the dark but we can see in black and white (quite well after a few minutes, after the eye adjusts).  Also we can see nothing at the centre of our vision.  The brain fills in this bit of information for us!  Yes that's right, the brain actually processes an incomplete picture and fills in the gaps in the middle and around the sides with what it "thinks" should be there.  It also does this for colour in our peripheral vision. google it.  Imagine if you bought a brand new LED TV screen and it gave you a picture like that - It would be in the bin straight away. Unfortunately we have to struggle on with our old eye design for the time being.  It works very well 99.99% of the time though.  The other 0.01% of the time we think we saw something else (or the brain makes it up for us!). Strange but true.

The brain basically does not like anything unknown.  In fact it cannot stand the unresolved.  If the brain does not recognise something it receives from the eye (due to distance or low lighting or the first look at something it has never seen before) it will do this.... and this is the important thing to understand.... First it will try and make it fit into the shape of a person, then it will try and make it fit the shape of an animal, then it will try and make it fit the shape of a know object.

This is why some people "see" what they think is a person or dark shape/ object when it is dark. because of how the brain processes the "poor quality" information from the senses. Also you can't see in colour when its dark! and you have a small hole in your vision in the very centre of the eye.  You think you see a white or black shape (which the brain misleadingly turns into a human shape) and then when the light comes on, or you fully wake up, the thing you think you were looking at turns back into the cat or bedside lamp!

I have experienced this phenomenon myself when walking home from the pub late at night and I took a short cut on a path through a dark tall oak tree lined park.  I saw a person (you guessed it, in black) hiding behind one of the trees, about 2/3 of the way down the path.  I had drunk one or two shandies, so was feeling brave and took the path anyway, (thinking that I would be able to take pretty good care of myself if I got into any danger).  I stopped about 1/3 of the way along and almost turned back, as this guy looked quite a bit bigger than me and he was crouching on the floor behind the tree, which seemed very suspicious.  I stared for about 20 seconds - definitely a large man hiding behind a tree - about to pounce on me if I went that way.  If I had turned back that night I would have been 100% convinced I saw a man there (or ghost perhaps?).  Anyway I continued.  Got a bit nearer and guess what?  Thats right, it was a dog, going to the toilet beside a tree, I could clearly see its tail wagging and its nose.  If I was scared of dogs I'd have turned back and I would have realised that I only saw a dog that night and not a man hiding.  Except that I wasn't scared of dogs, even big ones, so I carried on and to my surprise it wasn't a dog at all - it was a thick branch with bark on that had fallen off the tree, the leaves slowly moving in the wind.

So - 3 options there as to what I could have seen.  It all depended on picking up more detail for the brain to process.  But I couldn't have seen a better example of how the brain plays tricks on you.  Unbelievable.

No time to go into the ears now, as I'm off out.  if interested google "cocktail party effect" and speach de-verberation for an insight into how the brain processes sound.  Also look at audio memory duration.

 

If you appreciated my time trying to explain the above, you are more than welcome, any time.  If you still believe in ghosts and invisible things.  I'm sorry I can not help any more, go back to the 13th century and continue being ill informed and ignorant.

 

Hope that cures your fear of ghosts.

Q