It's often argued that, in any scientific inquiry, the true test involves replication. When it comes to testing the validity of a particular medium, we're sometimes told that if the first sitting goes especially well, we need to schedule a second or even third sitting in order to confirm our initial experience.
Something about this has never set quite right with me, and it's not a policy that I've followed myself. For instance, I had a very successful sitting (over the phone) with the medium Georgia O'Connor a few years ago, but I've never scheduled a follow-up. Lately I asked myself why.
There are a number of possible explanations. First, there's what the parapsychologist Charles Tart has called "fear of psi." There may be a deep-seated aversion to paranormal phenomena that affects even those of us who are inclined to believe in such things.
Second, there's an interesting point noted by Michael Crichton in his memoir Travels, in which he recounts his experience at a spoon-bending party. He found that he was able to bend the metal with no apparent effort, as were many people around him. But he also found that after a while he lost interest in the phenomenon. Spoon bending was boring! Logically this seems to make little sense, since the ability to manipulate solid objects by means of mental power ought to be the least boring thing in the world. So perhaps it's another aspect of fear of psi – a defense mechanism to protect us from delving too deeply into these things.
Or perhaps it really is boring, once you know you can do it. It's well known that card guessing experiments often show a decline in results over time, presumably because either the test subject or the experimenter (or both) gets bored and loses focus. Having played around with some online card guessing experiments now and then, I can say that I get bored with the game after no more than twenty minutes, even if I happen to have scored fairly well.
Another possible factor is confirmation bias. If we've had a particularly successful session with a medium, we may be reluctant to press our luck with a second session. We may prefer to hang on to the first session as something close to "proof" of life after death, while worrying (perhaps subconsciously) that a second session would undermine our confidence if it goes wrong.
Fear of psi, the possibly concomitant feeling of boredom with psi, and confirmation bias may be real enough, but they are probably not legitimate reasons to avoid a return trip to a medium. But I think there are other reasons that are more forgivable.
For one thing, a sitting with the medium – unlike, say, an experiment in chemistry – depends heavily on the emotional state of the sitter. There is reason to believe that a sitter with a sincere, earnest desire for an emotional connection will achieve better results. If we return for a second session, having already obtained the emotional connection we needed the first time, we may be driven by a less worthy motive – maybe the ego-based need to prove something to ourselves or to others. It's possible that this motive is not conducive to the best communication.
There's also a question of the communicator's motivation – that is, assuming that there really is a communicator involved. If the deceased has said everything he needed to say the first time, he may not come through again. Or, having done all he could in the first session, he may feel that further communication is pointless inasmuch as the sitter will always revert to skepticism. In addition, it seems that many communicators remain in contact with the earth plane only for a limited time before moving on to higher planes where communication becomes more difficult.
Then there's the medium herself. She is not a machine, and as with anyone relying on intuitive abilities, she is going to have her ups and downs, her good days and bad days. The precise conditions necessary for good communication are unknown and may involve such variables as the medium's mood, health, and alertness, and perhaps even outside factors like the weather. It's as unreasonable to expect a dazzling performance at every sitting as to expect a home run every time a good hitter is at bat. Even the best hitters manage a home run only a minority of the time. That doesn't mean they can't do it; it just means that hitting a home run is a complex intuitive skill that is not fully under the player's conscious control.
Finally, we might consider whether replication really is the gold standard in science. The emphasis on replication derives largely from the physical sciences, like physics and chemistry, where the same experiment can be performed over and over again, consistently yielding the same results.
But there are other sciences that don't depend so much on replication. Field anthropology comes to mind. In many cases, the observations recorded by a particular field anthropologist are not seconded by other observers. Occasionally a set of observations will be challenged, as was the case with Margaret Mead's reports of life in Samoa, but mostly the observers are trusted as being reliable.
Parapsychology probably has more in common with anthropology than it does with physics or chemistry; like anthropologists, parapsychologists study people, sometimes in their home environment. A parapsychologist investigating a poltergeist outbreak in someone's house is more like a field anthropologist observing an unfamiliar social situation than like a chemist mixing chemicals in a beaker.
None of this is to say that repeated visits to a particular medium can be of no value. A lot depends on the reliability of the medium herself. Charles Drayton Thomas did excellent work over a period of decades with the medium Gladys Osborne Leonard, and Richard Hodgson is equally well-known for his long work with Leonora Piper. But Leonard and Piper were two of the most powerful full-trance mediums ever studied, and full-trance mediumship in general probably yields more consistent results than the light-trance mediumship generally practiced today.
Moreover, even Leonard and Piper were not always on target; both had significant failures and both produced a lot of "bosh," to use William James's term. (Michael Tymn's biography Resurrecting Leonora Piper does a good job of separating the wheat from the chaff, focusing on Piper's most impressive hits, many of which were truly spectacular.) It should be pointed out that a great deal of patience was needed to carry out these time-consuming investigations; Hodgson devoted all his time to the studies – something that's not an option for most of us in our own inquiries.
Speaking personally, I don't feel a strong need to talk to Georgia O'Connor again, at least right now. I don't think my motivation would be right, and I don't see that I could gain much from the experience. Maybe I would get a little additional evidence to support the genuineness of mediumship, or maybe the session would be a bust, but in either case the original session, which I recorded and studied in detail, still happened and can't be explained away.
And if we expect to achieve absolute proof, we're probably asking the impossible. There seems to be an element of ambiguity and doubt built into this whole subject – what George Hanson dubbed "the trickster." If our everyday reality is, as Roger Ebert said in his final days, "an elaborate hoax," then we probably are not meant to see through it in any final way. The man behind the curtain must remain hidden; the show must go on.