The greatest scientific minds on Earth once thought the Earth to be flat, then they thought that the Earth was at the center of our solar system. If you really believe that all of the wonders of our universe can be explained by a man in a white coat with a bunsen burner, then I feel sorry for you.
This is rapidly veering off-topic, but the burden of proof is not on the skeptics to disprove the existance of ghosts, but on the believers to prove it.
Second, the 'flat earth' theory was not as widespread as believed - at least, not amongst sailors.
Erasthothenes actually managed to calculate the circumference of the earth to within 1%, over a millenia before Leif Ericson. All of the mathematics of navigation is predicated on a curved surface; even superstitious 15th century sailors instinctively understood that the world wasn't flat. The fear among Columbus' crew was not that they would fall off the edge of the world, but that they would be stranded in the ocean, dying of thirst in the middle of nowhere.
I don't believe that humans have discovered all of what the universe is. Heck Scientists can't even properly explain "dark matter" yet.
I am not closed to the possibility of ghosts, because I believe that as a species we still have a long way to go in the knowledge department.
Dark matter is something different - it was first theorized based on available data, then its existence was confirmed decades later based on continuous observation and experimentation.
Ghosts, ESP, astrology, etc - these are all typically offered as an explanation based on the lack of data. I don't necessarily preclude their existence, but I'm going to need some very compelling evidence to even begin considering the possibility ahead of more mundane explanations.
Anyway, back to the OP: my dog is afraid of her own food bowl - I had to lay a towel down under the feeder in order to get her to eat. We've all had experiences where our dog freaks out when encountering a person wearing a backpack, or a hat, or with an arm in a cast, for the first time. Given all this, is it more likely that a dogs can detect a ghosts, or that they are reacting to a particular object, scent, or sound that we don't even notice ourselves?
And yes, I'm a contributor to the
James Randi Foundation.