Each of us has a semi-coherent theory of the world; I’ll call this a personal belief system. Perhaps this is easy to understand through protypical characters: Religious Joe (RJ) and Secular Mary (SM). Religious Joe’s parents are evangelical, fundamentalist Christians. As a youth he went to Sunday School each week and the majority of his friends and their families shared common beliefs. Joe’s parents taught him “where we came from”, taught him that God was person-like and the bible was literally true. As Joe grew older he began to hear his minister and teachers more frequently.

Although Joe’s parents appeared wise, to Joe, they said they had limits to their knowledge. The wisest person they knew was the minister. They encouraged Joe to go to the minister with tough questions. Joe did this and he was, mostly, satisfied. Certainly, the minister could talk eloquently to any question Joe would ask, and Joe understood that the minister had studied many years in order to generate such clear answers to questions.

Mary’s development was in stark contrast to Joe. Both of her parents are artists (father an actor, mother a poet). Young Mary worshipped her parents; both were beautiful and extremely gifted. Although both of her parents called themselves “agnostic” or “not sure”, they rarely spoke of God. When Mary asked deep questions, such as “where to we come from?” or “what happens when we die?” or “who was the first person?”, her parents tried to make coherent answers, but were inconsistent. Mary never attended a church regularly, but in high school she accompanied some friends to a quaker service. During middle school and high school she formed close attachments to teachers, who gave more coherent explanations than her parents. In high school she called herself ‘existentialist’. In college she became a philosophy major. She read all of the major works and made a close friendship with Professor Lombardi, who helped guide her through philosophy. Mary considers herself a realist, who bases her view of the world on facts and has little truck for spirituality. Although not a scientist, she has taken science classes through high school and college. She has good familiarity with evolution, atomic theory, the ‘big bang’ theory, etc. She has also studied anthropology, sociology and political science, and she feels she has a good grasp of how the world works.

I’ve outlined two very different, but internally consistent world views. For both Joe and Mary, almost everything makes sense. Each can generate reasonably consistent descriptions of themselves, their world and the universe.

But they can’t both be correct. Who is right? As a secular person, I side with Mary, but that is not an argument. The point in both of these stories is that neither Mary nor Joe learned about their world through direct experience. For each, the entirety of knowledge, as I described it, was passed down from people they trusted, people (or books) they considered experts. So, if you are Mary or Joe, how would you go about convincing the other that you are right and he/she is wrong? One answer is: do an experiment. Acquire direct data from personal experience that is consistent with one world-view and inconsistent with the other. I’m a bit stuck here. I can’t think of a critical experiment. Perhaps you could do an experiment to watch life-forms evolve. Not easy. Or perhaps you could replicate a fundamental experiment in physics or chemistry? Again, not easy. Even if either of these experiments were performed, would it convince you? Couldn’t there be alternate explanations?

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.

We live in a highly complex universe. Most of what we call our knowledge of the universe comes from culture; that is, it is passed from one individual to another, rather than having each individual learn on his/her own. We don’t feel that way at all. Each of us feels he/she has a deep understanding, and that we are clear-eyed observers. But we are kidding ourselves. Given any area of knowledge — literature, nuclear physics, climate change, psychology — the set of true experts is extremely small. Experts are the scientists who can perform and understand experiments whose outcome creates the cultural database of knowledge (or the database of a particular belief bubble).

I’ll finish with one pertinent (and extremely annoying) example: climate change. In the course of the last decade I’ve gotten into numerous arguments about climate change. I believe in anthropogenic climate change — the gradual warming of the earth due to human activity. What’s my evidence for it? Experts I trust told me so. That’s it. On two or three occasions I’ve learned the scientific basis for these opinions. But that’s irrelevant. I would have to study for, perhaps a decade to have a personal opinion that mattered. No amount of fancy talk could push me one way or the other. In such a complex area I rely totally, totally, on the opinions of people I consider experts. It is possible that my judgement of who is an expert may change, but that is the only thing that could change my opinion.

We consider ourselves experts, that we think for ourselves. But for 99% of our knowledge, we rely on the authority of others.

Update: A few readers (including some in my family) feel that I come across as an intellectual relativist: that there is no difference between the two bubbles; that each is equally valid. This is not true. Mary’s bubble, the one I belong to, is the enlightenment bubble, the group that uses the scientific process as its epistemic process. The group that Joe belongs to uses divine inspiration as its epistemic process. I believe strongly in the scientific process. Of the two, its the only one that can correct errors, learn from mistakes and evolve. Moreover, the scientific process has given rise to remarkable techlology that dominates our lives; devices that we ALL believe in and rely on. A second clarification is that reliance on experts isn’t evil. In fact it permits the vast extension of our aggregate knowledge. But reliance on experts is a necessity we should understand and acknowledge. Commenter doesmindmater below illustrates a final point. It is possible to move from one epistemic bubble to another. The underlying theme of this essay was not that movement from inside to outside of a bubble is impossible. It is possible, but very hard.

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*epistomology is a philosphical term refering to the means of acquiring knowledge. “Epistemic closure” means that an individual only accepts knowledge within the confines of his/her ideological bubble.