LMNO thought I should crosspost this from Facebook, so I am.
The first conclusion of this essay is that many of us live in different worlds with different personal belief systems. And, although many of us believe that ours is correct, it is no trivial task to convince others. Once a belief system is developed, it is, almost completely, locked in. The term epistemic closure* has been popular recently. Each of these systems is self-consistent and forms a bubble of epistemic closure. When a person is in one closed belief structure, ideas outside of that structure just seem crazy. Within the structure, things make sense. There is logical consistency and no cognitive dissonance. Trying to believe ideas outside of a belief bubble creates creates ideational tension and is not stable.
The second conclusion of this essay is that most of our fundamental knowledge is not acquired by personal interaction with the world, but is delivered by experts. People cannot just call themselves experts, however, and be experts. The set of experts that Joe trusts has no overlap with the set that Mary trusts. Both Joe and Mary think that the experts outside of their bubble are fanatics, and, possibly, evil.
http://coronaradiata.net/2012/12/07/on-the-role-of-experts-in-creating-personal-belief-systems/It was rather challenging to read this, because as a scientist I mostly take my map for granted. I hold strongly that it can be changed, but it is still true for me as it is for everyone that at least some of my beliefs are expert derived rather than experience. Strike that, most are expert derived. When I think about this I realize just how shaky my own beliefs are, so much more so than fundamentalists who are sure of themselves. It's not the fact that they can change that make them shaky, but the lack of confidence from direct experience. I may witness firsthand certain chemical reactions, but I take the rest of the expert advice on chemistry through extrapolation and consistency. Likewise for most other things.