The world is full of stories about ghosts and haunted houses, Ebay is a festering cesspool of ghosts and haunted items for sale. The sellers see ghosts frequently, and many seemed to enjoy the most intimate and convivial relations with them. I wondered if these stories could possibly be true Were these ghosts real? After giving the matter some thought, I concluded the answer to be yes and no. First, I had to decide what I meant by "real." Controversies between skeptics and believers in paranormal phenomena often turn on what the parties mean when they say something is real. The scientist says, "We can't observe this thing, much less reproduce it. We have to assume it's not real." The believer says "So what? It was real to me." What are they talking about? To science, an event is real if it is objectively real. That is, if it exists in a world outside of and independent of our minds. Subjective events take place within our private thoughts and feelings. Subjective events may feel intensely real to us, but they may not refer to, or connect with, anything objectively real. Contrary to what many think, science does not claim to deal with all possible kinds of knowledge, but only with public knowledge. Public knowledge is an event which is available to anyone, believer or skeptic, anytime, anywhere. We can reach a consensus about the truth of a public knowledge claim by checking it against experience, but we can't do so with purely subjective knowledge. So skeptics want to know if ghosts are objectively real, like water is real, or other people, or tables, or clouds, or electrons and all the other furniture of the physical universe. Skeptics certainly don't deny that people have strange and powerful experiences; we just want to know if those experiences point to anything in this real world. I believe that ghosts are not objectively real. First, no ghost story or photograph which has been thoroughly investigated in human history has held up; and, second, there are plenty of good explanations for why people have ghost experiences (or think that they did). Those interested in the history of ghost research may consult D.H. Rawcliffe's Occult and Supernatural Phenomena, or R.C. Finucane's cultural history, Appearances of the Dead. Suffice it to say, diligent investigators always seem to find that memories are faulty, that critical corroborating facts do not exist, and that witnesses, if more than one, tell contradictory stories. Usually the ghost tales expand upon the telling and become more and more fantastic. A recent example is the "Amityville Horror" hoax, which spawned several books and one bad movie as it ran its course. More interesting to me are the reasons why people believe they have seen a ghost. Most of the time our brains are pretty good reasoning instruments, but occasionally they fail us. Psychologists have learned a lot about how this happens, and the results are fascinating. These anomalous experiences include hallucination, hypnogogic and hypnopompic dreams, fantasizing, memory confabulation and the feeling of "missing time." Anomalous experience is not limited to mentally disturbed people; it happens to all of us normal people now and then. For example, hypnogogic and hypnopompic dreams are hallucinations that occur upon falling asleep or waking, respectively. The sleeper may feel paralyzed or floating out of the body. He usually sees ghosts, aliens, monsters, or some such creature, and the experience seems very real, much more so than the typical dream. Psychologists estimate that fantasy-prone personalities make up perhaps 4% of the population. These people are perfectly normal except that they tend to fantasize much of the time, fully experience their fantasies with touch, smell and hearing, and are easily hypnotized. They also tend to mix their fantasies with memories of real events and construct new memories which seem real but are not. This process is called memory confabulation, and we all dolt to some degree. Fantasy-prone people are in no sense crazy. They just exhibit a part of normal brain function to a greater degree than most people. Obviously, such persons are likely to see, or remember that they saw ghosts, and sincerely believe their memories are real. For these and similar reasons, I don't believe that ghosts are real. There is no objective evidence for them and no scientific proof whatsoever, and I might add, there are perfectly good explanations for most ghost experiences. Still, if I am mistaken, I would like to be the first to know. If any reader knows where I can observe ghosts or haunted house activity with a large group of people at the same moment, please get in touch with me. To date, there is no evidence of a mass public viewing in recorded history that is considered credible evidence, period. It’s basically a sideshow attraction derived to part one of his money.