I think there are two different paths by which people come to believe in things. I call them type E and type A beliefs.

Type E beliefs are evidence-based. People assess the available evidence for a proposition P and, once convinced, come to the logical conclusion and belief that P is true. If the evidence is insufficient, P is unproven and the belief in P is not adopted.

The belief is impermanent. If the evidence is later found to be less certain, or if at any time convincing evidence is found to the contrary, then belief in P must be abandoned (which does not however mean a belief in not-P). This type of belief is rational, dispassionate, scientific and relatively uncommon.

Type A beliefs are authority-based. People assess two things: authority and consensus. The authority is a person or institution commanding respect, and is responsible for originating or disseminating the proposition P, and clarifying its detail. People must first believe in the authority, but this is usually not enough. They will typically then look among their community of peers for signs that the authority is to be believed on this subject. Once this consensus is found there is a natural assumption that the authority is correct and P must be true. At least there is little fear of contradiction!

Such a belief tends to be permanent. Flaws in the evidence or contrary evidence have no effect whatever on the belief. Only when the authority falls from grace or there is a shift in the consensus can the belief ever change, and this is a rare occurrence. This type of belief is emotional, sometimes irrational, typically unscientific and very common.

So where does this get us? It seems pretty obvious that we should trust our type E beliefs, and be suspicious of our type A. It doesn’t always work that way.

The whole of science is supposed to be based on type E beliefs. From time to time individual theories take on type A characteristics, which makes them hard to dislodge and all the more disruptive if they finally have to be abandoned.

Religions, parapsychological phenomena, alternative medicine, superstitions, horoscopes, indeed many or most of our day to day activities are based on type A beliefs. For many people, this is what works.

You can debate someone who holds a type E belief, if you can offer better evidence, and sometimes you will change their point of view.

There is truly no point in debating someone with a type A belief on the basis of evidence. The only possibility is to offer superior authority, and with a religion that can be hard to achieve.