Originally Posted by Cosmic Yak
That's part of the rhetoric. There is an informal rule of debate that says, "If you're explaining, you're losing." Claimants of the supernatural pepper their critics with anecdotes in order to keep them on the hook to provide explanations. Naturally since these anecdotes invariably occurred far away and long ago -- if they even occurred at all -- the critic has no chance of success. What the claimant has to account for is why these purported gifts wholly disappear when they occur under conditions in which we can
acquire a multitude of evidence that would eventually let us reason between various possible explanations. The rhetoric is built entirely around keeping the claims practicably untestable. Any time the critics try to get out in front of all the problems with anecdotal testimony, the spiritualists scramble to declare themselves exempt. This is how we know what they know they're relying on.
And that phenomenon has been repeatedly observed. The claimant remembers the encounter with the medium far more favorably than an objective record of the encounter reveals. This is why mediums generally want to interact only with people who already predisposed to believe their claims. This rosy recollection appears to be one of the psychological factors that practitioners rely on.