One point on the Sharon James letter. YOu give Sylvia a 50/50 on saying her son would be found alive/return.
However, the information provided indicates that Ms James told Sylvia in her reading that her son had a history of disappearing and returning (on multiple occasions).
This clearly wasn't a 50/50 bet for Sylvia. Faced with the same call, I would tell the subject that her son would return/be found alive (yet again), expecting a better than 50% chance of being correct.
I would like to take this point and expand it with a slightly different flavor.
In so doing, I acknowledge taking an argument from Richard Dawkins's
The God Delusion, and adapting it to the circumstances at hand. In
The God Delusion, Dawkins cautions against assigning probabilities where evidence is scant either way. The evidence
for the existence of a personal deity who interferes in personal affairs may be scant, and the evidence
against such a deity may be equally scant. But that does not mean that the odds of such a deity existing are 50/50.
My point is not to argue religion or metaphysics or supernatural intervention. I merely mention Dawkins because his work inspired me to make the point.
Indeed, the point can be made without reference to any supernatural aspect. If we know that two football teams are to be matched against one another and we know that there can only be one of two possible outcomes (either one team will win the game or the other will win), it does not necessarily follow that each or either team has a fifty percent chance of winning. To make an intelligent estimate of probability, we would need to know more than just the fact that there are two possible outcomes.
In this case, as Geckko pointed out, there was evidence to suggest that, based upon past experience, one outcome was more likely than another.
Now, I make this point not so much as a criticism of the StopSylvia site, but as an observation that one must carefully evaluate the legitimacy of percentages assigned to various outcomes. Self-proclaimed psychics do this a lot, puffing up their numbers so as to boast greater success than they actually have. Accordingly, if we as skeptics think charlatans must be more honest when using percentages, then we must be more mindful when using percentages ourselves.
