And given how old civilization is, I bet someone probably died within 1000 feet of where you live right now.
Certainly hundreds of animals have died around you for sure, many within your lifetime.
In fact you probably ate a dead creature today.
WTF is with people and "ghosts" ?
It's weird to me how so many people's approach to mythbusting is "if ghosts were real, they would behave according to this set of rules I just made up, and they clearly don't, therefore ghosts aren't real." A much better argument would be "There is no evidence whatsoever of ghosts existing, therefore ghosts aren't real." There's no need to try to define ghosts as elementary particles or whatever.
Unless you live at the top of a tall skyscraper. Civilization is old, but people living in mid-air isn't!
And they all forget to count ghosts from microorganisms and insects.
Also bear in mind that, if one believes in reincarnation and animism, "ghosts" on earth may be considered a special case, when the expectation is that most spirits rejoin the karmic cycle (or whatever.)