Evidence and Belief

Belief is discussed thoroughly in The Meaning of Life: A Guide to Finding Your Life’s Purpose. It discusses how a belief is anything that you accept as existing or true and how knowledge is a subset of beliefs that you can prove to be true. The problem is that—if you were getting technical—you can only truly know something (e.g., “Did I leave the stove on?”) by observing it in the present moment; everything else is a belief. So, what happens is that you observe something, draw a conclusion based on evidence, and then that becomes what you know to be true until you receive enough evidence to the contrary that would get you to change that belief.

Here’s the problem: the amount of evidence required to form a belief is exponentially less than the amount of evidence required to change a belief. Psychologists contribute this to factors such as the Primacy Effect, which is how people tend to remember the first facts/evidence that they see and give it more weight in how they evaluate the situation from that point on. Colloquially, we know this as a “first impression” where if the first thing you see someone do is trip, you’ll likely think of them as klutzy for a long period of time afterwards—even if that is the only time they’ll ever trip in their life.

To make matters worse, we also tend to jump to conclusions where we take just a little bit of information and extrapolate or fill in the details to tell a whole story. In combination with confirmation bias, we fill in those details with what would validate our beliefs and assumptions about the person or situation. Finally, add in attribution bias, and then we assume that the situation is representative of the entire person’s personality and not just a happenstance.

Note how this set of psychological heuristics all work to lead people to have a whole slew of beliefs about a situation that are likely to be imperfect at best—or blatantly false at worse—and yet they then hold them well past the point that evidence delivered to them in the first place would have convinced them otherwise. This isn’t even including additional effects like projection where, for example, if you were cheating on your significant other and then saw them get a random text message and jumped to assuming that they were cheating. The erroneous belief train is long and hard to stop!

Think about how badly this can affect you in many situations:

• Politics – Your party is better than the other party, so every news story about the other party just tells you how bad they are and every one about your party is lying on the part of the other party. You will go to your deathbed thinking that any wrongdoing was a hoax.
• Worldviews – You think that people are generally dumb and then see a news story about how “Actually, we’ve been getting dumber since the 1800s”—no matter how many links (e.g., here and here) and basic factual explanations of how IQ scores work (i.e., IQ is averaged at 100 and so it’s impossible for the average IQ to be anything but 100) are shown, you still think people are getting dumber. (Note: this is a real argument that I had with a smart person that inspired this post; the “evidence” that “owned” my points? “Nature ebbs and flows.” Seriously.)
• “The Science” – We saw this over the last few years: it didn’t matter what was true; it mattered that everyone needed to do their part and so all benefits were trumpeted and all concerns, risks, or complications were silenced. It doesn’t matter what evidence goes against what people in power want you to believe regarding hot topics—e.g., climate change, COVID, elections, corruption, school curricula, violence—all that matters is that you should listen to them and the only “science” that is legitimate is the one that confirms their hypotheses.
• Prejudice – Imagine that you saw a person do something out of context and assumed that they were evil and treated them like garbage only to find out years later that you were wrong about them? I always tell people, “Don’t commit acts that, if you are wrong about why you’re doing them, would make them grossly unethical,” for a reason: if you don’t have hard facts on what happened and commit unethical acts toward someone in what you perceive as justice or reciprocity, then you are the immoral person in the exchange because your acts came first based on false beliefs.
• Self-Confidence – If you believe that you are bad at something, you would have to be good for a long, long time before you changed your attitude about it—and, let’s face it, you’re probably going to give up long before that because of your initial beliefs.

I’m sure that there are many, many more. But here’s the thing: we all think that we’re rational individuals and, especially for someone who considers themselves “a person of science”, think that we would change our minds on a dime given new information. You hear that from pretty much every famous intellectual. And yet those exact same people will contradict every piece of evidence shown to them with their previous facts and continuously downplay new information provided to them because of their previous conclusions. In short, no one is immune.

So, what can you do? Well, you’ll always be subject to these biases, so you’ll have to be eternally vigilant if you want to fight them. And there’s almost no way that you could hold decades of beliefs and then see one contradictory point and say, “Oh, I’ve been wrong all this time!” It sometimes happens in therapy or with a dramatic demonstration of how something you thought was impossible could be done (or proving something you thought wrong in dramatic fashion), but it is pretty rare overall. The easiest recommendation to follow would be to ask yourself, “If the new information were correct, how should my conclusion change?” Add onto that, “If this were the only information I had, what would I think were true?” Finally, if you ended with, “What proof do I have in my old belief, and how does it compare with this one? Can these pieces of information both be true (and, if so, how do I combine them), or does one have to be right?”

No system will be perfect, of course, as false beliefs are inevitable without perfect information. But if you can make sure that you test your beliefs that you know you formed on little evidence or return to them to see whether this new information should influence you at all, then you’ll at least be open to changing your mind when you were previously wrong about something.

As a final point, note that we are strictly talking about the relationship between proof or evidence that you have and the beliefs that you hold about reality. Excluded from this post was the idea of faith: believing in the potential for a positive future without or despite evidence. I mention this because faith is key to being successful in life and requires that the person holding it believe in something without evidence—going so far as to ignore contrary evidence to keep the hope alive that a better future is possible.

Note that one can be firmly based in the current reality and simultaneously have faith in a positive future; since the future hasn’t been written yet, literally anything that is physically possible can happen (think of this as a “Reverse Murphy’s Law”: anything that can get better will be more likely to get better with a positive attitude about it). So you can be evidence-based for the past and present and still be optimistic about the future for the purposes of your mental well-being.

So the next time you hold a firm belief and someone provides contradictory evidence, take a moment to consider it. It could be wrong or fake, but so could your beliefs. Take just enough time to test your own belief as well as the new facts being entered as evidence, and you will do your best to ensure that things like the primacy effect don’t bias you toward erroneous beliefs just because it’s all you think you know about the topic.