Earl And The Earlites

Suppose you know someone - call him Earl - who joined a cult some years back, then eventually transitioned back into ordinary society. Suppose one day you came to know that Earl was of the opinion that Barack Obama faked his birth certificate. Suppose you hadn't really followed the birth certificate issue very closely. Then: how would your opinion about the birth certificate change, knowing that Earl was a "birther?"

A rigid rationalist will point out that this isn't fair. Just because someone is wrong about one thing doesn't mean that someone is wrong about everything, or even about most things. That same rationalist will also point out that truth doesn't depend on who believes what. And, of course, that rationalist would be absolutely correct, so long as what we are talking about is a rational, empirical true/false question.

But now suppose that you already know that the cult to which Earl once belonged was, as I like to put it, cuckoo-crazy. Suppose also that you have all the facts on the "birther" issue, which has now been analyzed so closely as to have left room for no reasonable doubt: the "birthers" are wrong. Now you know something about Earl, and what you know is that Earl is drawn to false beliefs.

You also know something about the kind of false beliefs to which Earl is drawn. Earl has a penchant for cultish beliefs. In one case, Earl was a member of an actual cult, and then in another case, he subscribed to conspiratorial, fact-immune, paranoia.

Now, suppose you learn that Earl believes a new thing. and this is yet another thing that you honestly believe to be false. But Earl is always arguing about it, passionately defending his belief in this third thing. At this point, you're already far beyond the point where Earl can persuade you to believe anything. His opinion doesn't influence yours at all. You're also fair enough and rational enough to avoid falling into the trap that "anyone who believes the same third thing that Earl believes is a conspiracy theorist." You give the third thing a fair hearing, you just don't take your information from Earl, you get it from more reliable sources.

But suppose, while you're looking at more reliable sources, you discover that there are a lot of other people like Earl, who all believe this third thing, and who also happen to be predisposed to cultish beliefs. Let's call them Earlites. 

Suppose, say, 30% of the people who believe in something are demonstrable Earlites, prone to cultish beliefs. The other 70% are, as far as you can tell, reasonable people. Suppose that 30% is an over-representation, though. Suppose that only, say, 5% of the human population is a demonstrable Earlite. So this third thing definitely attracts a lot of Earlites, even though they don't comprise the majority of people who believe in that third thing.

Finally, suppose you track a whole set of beliefs - a third thing, a fourth thing, a fifth thing, and so on - that all seemingly attract about 30% Earlites and 70% reasonable people, but that it's always the same set of Earlites

If nothing else, this would give you a great deal of insight into Earl's way of thinking. You might be no closer to knowing the truth about issues {3, 4, 5, 6, ..., x-1, x}, but you'd definitely know that the Earlite population is one that gravitates to a certain array of beliefs. You'd know that these beliefs are either cultish, or lend credence to a separate, uniquely Earlite, way of viewing the world. 

That would be good insight to have.