"Dr Crow" would just like to point out...
...that it'll be a couple more years before he can actually call himself "Dr." But thank you.

I will say, however, that there isn't much of a basis for your theory. It's a nice idea - very Dr Who, in fact - but the main problem is that the only reason we see an object is because light is being reflected from it. Take the photons reflected from a woman's skin 50 years ago as she walked down a corridor - they will have been scattered in all directions, and probably absorbed eventually. The chances of a similar combination of photons coming together and making for someone's retina are so small as to be virtually non-existent.

This is not to say I believe in ghosts. Personally I suspect they're just hallucinations, and perhaps the associations of certain places result in people seeing similar things.

EDIT: Should have read the other replies more closely, as everyone else has come to more or less the same conclusions I have. Oh, well.
(LongJohnBaldry, Sun 6 Jul 2008, 0:03, Reply)