I find this to be a fascinating question. Think about it. We all live in the same universe. The laws of the universe are the same for each of us. And we live on the same planet. Yet we have different political beliefs, religious beliefs, philosophical beliefs, and even different beliefs about science. Some people are Christians, some are Buddhist, others are Hindu, and others are Muslims, and yet others are something else. With Christian beliefs, there are Methodist, Baptist, Anglicans, Shakers, Catholics, and many others; some of these accept the others as Christians and some do not.
Some people believe what they believe simply because that is how they were raised. Because their parents believed xyz so they believe xyz. Other people seem to believe something to spite how they were raised. Their parents believe in xyz so they believe in abc. Others, however, seem to believe what they believe because they have spent a lot of time thinking about it. Yet, amazingly, not always does deep thinking produce deep reasonable results. I do not doubt that the Unabomber spent a lot of time thinking about his beliefs, while coming at the conclusion it was okay to kill people.
Some believe certain things because they are emotionally and mentally unstable. It may be that Unabomber was emotionally and mentally unstable. That is one reason some people believe some really weird stuff. However, that is not true of everyone. The evidence for global warming has been piling up for decades. Scientist after scientist has come to the conclusion that global warming is real. That global warming is real even makes sense, pump more gas into the atmosphere, and it will have to have some kind of effect. Yet many choose not to believe it and dismiss it outright. They think that because science can be wrong and because sometimes current theories are shown to be wrong, then global warming, because it is inconvenient, can simply be ignored. For the sake of their grandchildren, I hope they are right.
So why do we have different beliefs? Why do some accept the science of global warming while others refuse to?
I think beliefs are fundamentally emotional. I cannot prove that, but I think it has to be true. And we all have unique emotional parameters that cause us to feel life differently, to have different emotions to the events that can happen to us. Part of this feeling, I should add, is consciousness. Consciousness, I think, is primarily an emotion. I cannot prove this, but I suspect consciousness evolved from the emotional part of the brain. So different beliefs pander to different emotional sensibilities. A person who is very religious, for example, has different emotional needs than someone who is not religious. And some of those emotional needs are perhaps hardwired in the brain.
I will admit that I cannot prove this hypothesis, so do not try using it in your school report. But I feel, I believe, it has to be true.
I react pragmatically. Where the market works, I’m for that. Where the government is necessary, I’m for that. I’m deeply suspicious of somebody who says, “I’m in favor of privatization,” or, “I’m deeply in favor of public ownership.” I’m in favor of whatever works in the particular case. -John Kenneth Galbraith, economist (1908-2006)