So, in the last post (see PHYSICS OF GHOSTS 101: PART SIX B: WHAT IS IT, AFTER ALL?  CATOPTRIC PARADOX  -  I.) I gave you my explanation to what I call Catoptric Paradox. 

It is a well-established fact that sometimes a ghost can appear in a mirror, while it cannot be observed directly.  Essentially, the observer has to look into a mirror with his back to the room and see ghost in a room, while direct look into the room reveals nothing in it.  From the standpoint of simple optics this effect appears utterly impossible: all light in the room, all objects ought to be reflected in the mirror and hence they ought to be seen just as well as directly.

 
 
If you are following all my posts, then you’ve probably seen my previous one, where I’ve decided to leave for a moment the subject of ghosts and to praise the great books of Harry Potter (see HARRY POTTER – FOREVER!).  Now I am back on the subject, which I would like to start with a quote from this marvelous book.  This is a dialogue between Harry Potter and Nearly Headless Nick, the ghost of House of Griffindor, and it is right on the subject: