Psychological reasons for having beliefsThis type of beliefs, to which people hold on, may come under pressure by objective findings which contradict them. When this happens, several strategies, conscious or unconscious, may be used to hold on anyway to these beliefs. Previous research has identified some of those strategies, such as: derogating the source, criticizing methods, using fallacious reasoning, biased perception, and simply avoiding the topic or ignoring the findings.
Making beliefs unfalsifiableIn a paper by Friesen, Campbell & Kay (2015) yet another strategy is identified: making beliefs unfalsifiable. In other words: making them impossible to disprove. Here is an example to illustrate what is meant by this. A falsifiable reason for following a religion might be: I believe because archeological evidence supports my religion. An unfalsifiable reason might be: I believe because I feel God's presence. Another example. A falsifiable reason to be against same-sex marriage is because children of same-sex parents would somehow grow up badly. An unfalsifiable reason would be: because it would be morally bad.
Friesen et al. show that making beliefs unfalsifiable has both offensive and defensive advantages for the cherished belief systems. The offensive advantage is that you can hold your beliefs even more strongly and more fiercely attack its opponents. The defensive advantage is that it makes your belief resistant against contradictory facts. In 4 experiments the researchers demonstrate that these offensive and defensive advantages indeed happen, both in a religious and in a political context.