When you read a lot of material about the paranormal, you encounter all kinds of claims. Sometimes it becomes difficult to separate the strong cases from the weaker ones. It can even be confusing and discouraging, as the weaker cases start to overwhelm the stronger ones in your mind.
A possible approach to this problem is to ask yourself, "If this were the only evidence I had for a particular claim, would I believe it?" In this way, you can separate lines of investigation that otherwise might run together in your thoughts.
Admittedly, this method is somewhat subjective, since it depends on what you personally would accept as adequate evidence for any given claim. But at least it provides you with a method, however rough, for discriminating among the various strands of evidence that present themselves to you.
Here are some examples of my personal evaluations of different kinds of claims.
If the reports of people taking hallucinogenic drugs like DMT were the only evidence for the existence of other planes of reality, would I believe in those other planes? I would not. I would assume that the elaborate scenarios visualized by users of psychedelic drugs are woven out of the material of the unconscious mind.
If Robert Monroe's reports of his out-of-body experiences were the only evidence for such experiences, would I believe in OBEs? I would not. As I've written elsewhere, Monroe's accounts are frequently so bizarre that they sound more like dreams or hallucinations than real experiences.
If past-life hypnotic regression were the only evidence for reincarnation, would I believe in reincarnation? I would not. Hypnosis is not necessarily reliable as a method of obtaining factual information. Hypnotized subjects may confabulate to please the hypnotist, and may draw on long-buried memories of books and movies from years ago in order to fill out their narratives with convincing details. D. Scott Rogo's excellent book The Search for Yesterday offers a detailed examination of past-life memories obtained through hypnosis, and provides serious grounds for doubting their validity in at least some instances.
If the investigations of Ian Stevenson, and like-minded researchers such as Jim Tucker and Carol Bowman, were the only evidence for reincarnation, would I believe in reincarnation? Possibly, yes. At the very least, these studies strongly indicate that something paranormal — something that cannot be explained by any "normal" means — is going on. Whether it is reincarnation or some form of spirit obsession/possession or some other phenomenon, I don't know. But a lot of this evidence seems very good to me.
If the only evidence for psychokinesis were the reported phenomena of Uri Geller, would I believe in PK? Probably not. Too many questions have been raised about some of Geller's more bizarre claims — for instance, being in telepathic contact with extraterrestrials. Plus, there is Geller's undeniable gift for showmanship, which at the very least blurs the line between genuine phenomena and stage magic.
If the only evidence for psychokinesis were the reported phenomena of Eusapia Palladino, would I believe in PK? Probably, yes. Though Palladino was unquestionably capable of cheating, she also seems to have produced genuine phenomena in circumstances that preclude fraud. The 1908 Naples sittings are the prime example. I think it is highly unlikely that a team of very experienced investigators, who among them had debunked more than 100 physical mediums, and who observed Palladino in adequate light, taking strenuous precautions, would be completely fooled over a long series of sittings.
If the only evidence for apparitions consisted of the so-called "crisis apparition" cases collected by the Society for Psychical Research in the late 19th century, would I believe in apparitions? Yes, I would. The sheer quantity of cases accumulated by Edmund Gurney and FWH Myers, and the high quality of the better-documented ones, convinces me that crisis apparitions are a real phenomenon.
If the only evidence for mediumship consisted of the sittings of Edgar Cayce, would I believe in mediumship? No, I wouldn't. Most of Cayce's channeled information consisted of nostrums intended to cure various ailments. No systematic effort was made to determine if the cures were successful, and most of the remedies seem dubious at best. Cayce's predictions have sometimes proved incorrect, and his reconstructions of the past are also open to serious challenge by archaeologists and historians.
If the only evidence for mediumship consisted of the performances of contemporary TV mediums like John Edward and George Anderson, would I believe in mediumship? Probably not. Although watching John Edward on TV got me interested in mediumship in the first place, I could never rule out the possibility — however unlikely — that he was faking it in some incredibly clever way. After all, he controlled the venue, and most of his appearances were edited. While I think Edward is probably for real, I base this opinion on my knowledge of other mediums rather than Edward alone.
If the only evidence for mediumship consisted of the investigations of Leonora Piper and Gladys Osborne Leonard, would I believe in mediumship? Yes, I would. Both of those ladies were extensively examined by highly capable researchers over a period of 20 years. They remain the most thoroughly tested in mediums in history, and I cannot see any remotely plausible non-paranormal explanation for their accomplishments.
This is not meant to be an exhaustive list, obviously. But perhaps it gives some idea of how I would try to distinguish between relatively strong and relatively weak evidence. Once having accepted the stronger evidence, I probably do have a tendency to be more accepting of some of the weaker cases as well. For instance, since I think PK is possible, I'm more inclined to think Uri Geller can actually do it. But Geller's evidence on its own would not convince me.
It's probably natural to become less skeptical about certain areas of evidence when you have overcome your initial skepticism in related areas. But I do think it's useful to occasionally review all the evidence as dispassionately as possible, and to separate the wheat from the chaff.