I have often wondered how people can continue to believe something even though there is a mountain of evidence against the belief. I recently came across a psychological explanation of this called "Cognitive Dissonance." Leon Festinger (1919-1989), formerly a professor of Psychology at the University of Minnesota developed the Theory of Cognitive Dissonance. In a book entitled, When Prophecy Fails: A Social and Psychological Study of a Modern Group that Predicted the End of the World (University of Minnesota Press; 1956), he investigated a religious cult which had predicted the end of the world on a particular date but when the date came nothing happened. Some of the followers acknowledged they had been duped and went back to their old lives. The very committed ones, however, could not admit to themselves that they had been fooled and thus they came up with an alternative explanation. Perhaps it was not the end of the physical world but the end of a spiritual world.
The particulars do not matter. The fact is that when someone is committed wholeheartedly to a belief system and his or her whole life is shaped by that belief, it becomes very difficult to assimilate any information which runs contrary to that belief.
What is my point? I think this explains why most people who are committed to their religion or belief system will NEVER change their beliefs NO MATTER how much evidence is presented to them.
When I was a Christian, I used to be amazed at how intelligent people could continue to believe Mormonism even though there was so much evidence against it. One day I realized that I was just as guilty of closed-mindedness as they were. I would listen to the evidence against evangelical Christianity but only to "refute it." In other words, my mind was already made up. To entertain the idea that you may actually be wrong and that your whole life, which has been built around this false belief, has been misguided is extremely painful.
How does one eliminate this cognitive dissonance? According to Festinger, there are three ways to eliminate dissonance: (1) reduce the importance of the dissonant beliefs, (2) add more consonant beliefs that outweigh the dissonant beliefs, or (3) change the dissonant beliefs so that they are no longer inconsistent.
He gives a non-religious example of this phenomenon. Consider someone who buys an expensive car but discovers that it is not comfortable on long drives. Dissonance exists between their beliefs that they have bought a good car and that a good car should be comfortable. Dissonance could be eliminated by deciding that it does not matter since the car is mainly used for short trips (reducing the importance of the dissonant belief) or focusing on the cars strengths such as safety, appearance, handling (thereby adding more consonant beliefs). The dissonance could also be eliminated by getting rid of the car, but this behavior is a lot harder to achieve than changing beliefs.
Precisely because it would be traumatic and painful for one to give up their firmly held religous beliefs, people will rarely exercise option #3. So they tend to either minimize the importance of the dissonant beliefs or try to counterbalance those dissonant beliefs with more consonant beliefs.
For example, take an evangelical Christian who believes in the inerrancy of the Bible. When confronted with the strong evidence against inerrancy, the believer might respond: (1) "Well, inerrancy, does not really matter because the Bible is a spiritual book and in spiritual matters of sin and salvation, it faithfully accomplishes it purpose;" (2)"Well, there are many great things in the Bible and I will focus on those;" or (3) "I must give up a belief in inerrancy." Most heartily resist conclusion #3.
As pointed out in the previous post, it seems most people believe in their religion for emotional reasons not intellecutal reasons. Thus, the probablity of them rejecting their religion based on intellecutal concerns is remote. A few brave, honest souls will but most will not.