Something that you believe is obviously a belief. To be more precise, a belief is a statement about the universe that the holder believes to hold true. The sum of all the things that you believe is your “belief system”. And, once again, to be more precise, a belief system is the sum of all statements that the holder believes to be individually true.

Everybody has a belief system. Without it, we wouldn’t have any way to make sense of anything from the smallest question such as ‘why does water flow downhill’, to the biggest of questions such as ‘what is the meaning of life’.

So what defines a good belief system and how could one belief system possibly be objectively better than another? There are three qualities of a belief system that are very important; coherency, completeness, and reality. I will explain these ideas in some detail below although not in the order just given.

Reality

The individual beliefs in a belief system must comport with reality. It is possible to have a completely fantastical belief system, only if you’re unlike most people (i.e. you’re completely insane).

What I mean is that your beliefs must agree with what you see in reality. If you stub your toe really hard and you firmly believe that you did not stub your toe, then your belief does not comport with reality (and you are most likely insane).

Such a belief system is useless because it does not help you make accurate predictions about the future. Life is all about making accurate predictions. For our entire lives, the sun has risen every morning. Based on this evidence, we form the belief that the sun will always come up in the morning. Based on this belief, whether or not we think about it, we make the prediction that the sun will come up tomorrow morning.

If for some reason, the sun stops rising in the morning, then our belief that the sun will always rise in the morning, does no longer comport with reality. When that happens we are forced to discard the belief and search for a new one. Perhaps we’ll revise our belief to ‘the sun sometimes rises in the morning’. If after a long period of not even that happening, we would be forced to revise it even further, to something like, ‘the sun used to rise in the morning’.

Coherency

Coherency is about how well one’s beliefs make sense when more than one at a time are considered. A coherent belief system is a belief system in which all the individual beliefs fit together in such a way as to create a solid whole. A belief system that contains contradictory beliefs is not coherent.

For example, suppose you held the bizarre belief that all Mennonites are weird. You also hold the belief that a certain friend named Sam is a cool dude and is not at all weird. Then you find out that Sam is a Mennonite. Suddenly you realize a contradiction in your belief system. On the one hand you believe all Mennonites are weird and on the other hand you believe that one Mennonite is not weird. These two beliefs do not fit together. Taken one at a time, they might make sense, but taking both at the same time results in a logical contradiction.

An incoherent belief system is bad. If you hold contradictory beliefs in your belief system it must logically be the case that at least one of your beliefs does not comport with reality. It is false. This tends to cause confusion and cognitive dissonance – neither of which are good attributes to possess in this complex life.

Finding contradictions in one’s belief system is actually quite common for the serious thinker. That’s because we are all operating on incomplete information. None of us knows everything and no matter how strongly we believe in something, new information could pop up which totally disproves our belief. Finding a contradiction can actually be a refreshing experience because it gives you the opportunity to explore intellectually and perhaps to happen upon bigger truths.

It is a common tactic for debaters (think atheist versus Christian) to attack the coherency of the other person’s belief system in an attempt to find and display a contradiction in the opponent’s belief system.

The important thing is that you remove the contradiction. Think about the conflicting beliefs because one of them must logically be false. Are all Mennonites really weird? Is Sam really a cool and completely non-weird guy? In your investigation into the basis of your opposing beliefs you may just stumble onto something new. Perhaps not all Mennonites are weird after all!

Completeness

The last quality of a belief system is “completeness”. This idea is related to how big your belief system is. Are there still questions that you don’t know the answer to? Of course there are! Our belief systems will probably always be incomplete but yours can be more complete than your neighbor’s.

The completeness of one’s belief system can be deceptive. This is particularly true when it comes to religion. Believing that God does literally everything is a pretty damn complete belief system isn’t it?

Well, no because as it turns out, this belief system actually just skips over everything. Take earthquakes for example. Years ago, many people thought God caused earthquakes and that was that. This idea was an explanation for earthquakes but it was useless. It was of no help in predicting earthquakes nor in gaining a better understanding of the overall workings of our planet. Nowadays we know about plate tectonics – how the plates move about on the Earth’s surface, grinding against each other, pressing against each other, and suddenly releasing tension. This explanation of earthquakes is more complete – it is more useful. It helps us predict earthquakes, it helps us gain a better understanding of how the Earth works as a whole, and it even helped explain several things in evolutionary theory that had previously been mysteries.

Updating Your Belief System

We are often given new information. Our job is to analyze that information and ask ourselves if it makes sense with what we can see of reality. If it does, we need to ask ourselves if it is coherent with our existing beliefs? If so, the information is quickly incorporated into one’s belief system but if not, the information must either be discarded as false or one’s belief system must be revised.

When it comes to larger chunks of information (such as the theory of evolution), it is wise to take a little more time to ensure that everything in the set of statements actually coincides with reality. If it does, then we need to check the internal coherency. Do all the statements within the set, make sense when taken as a whole (remember to disregard your own beliefs through this process)? If it comports with reality and has good internal coherency it is time to see how well it would fit with the rest of your belief system. If there are conflicts then things start getting interesting. On the one hand you have a scientific theory that explains reality quite well but on the other hand it doesn’t fit with your beliefs about the nature of reality.

Now you need to start thinking hard. Could you modify your existing beliefs enough so that evolution could fit inside without causing coherency problems? If so, would the resulting belief system be better than your current one? Would it be more coherent? More complete? If so, there’s only one viable option. Revise your current belief system enough so that you can import the new segment.

When I first studied the evidence for evolution I marveled at the how well it explained some of questions that I had often wondered about. It appealed to me because it mirrored reality so well and it was so much more complete than my existing beliefs on the subject – that God created man and all the animals. However, I couldn’t be expected to just drop the idea of God entirely. My beliefs about him were entwined with all the other beliefs in my belief system. So I started wondering if I could believe in both. As it turns out, I could – as soon as I re-interpreted the Bible as more of a metaphorical work than a literal work.

Rarely does a person’s entire belief system change overnight regardless of how much evidence is thrown at the person. It is often easier to live with contradictory beliefs than it is to completely switch a belief system. This is particularly true for belief systems that are well established in a person’s mind. I’m referring to religion and how it is often indoctrinated starting at a very young age.

Judging from my own experiences, I believe it is essentially impossible for a firm Christian to become an atheist in any short period of time (despite having been born atheist, mind you). For me the whole process took about 10 to 12 years.

So if you are intent on changing someone’s belief system – don’t try to do it overnight. Work on one or several beliefs at a time rather than the whole system at once. You increase your odds of eventually succeeding.

Note: In this last section, I have approached the issue of updating one’s belief system from the perspective of someone watching your mind (metacognition). When it happens to yourself, it will not seem quite this analytical. In fact, many of these steps will be taken by your mind without you even realizing it.