When my kids were learning to talk, they would often make up words to overcome shortcomings in their vocabularies. They knew, for example, that baby dogs were called “puppies.” But since they didn’t yet know “foal,” a baby horse was called a “horse puppy.” Similarly, when my wife needed an oil change, she would go to the “car doctor.” It didn’t bother them that no one else used these terms. They described the places and things that they needed to using the words they had. Looking back on it, it reminds me of Randall Munroe’s  Up Goer Five, in which the XKCD author explains how the Saturn V rocket worked, using only the 1000 most-used words in the English language.

Cognitively, the children were taking new ideas (there’s a place where we go to get the car fixed) and attaching it to what they already know (when I get sick, I go to the doctor). Later, they refined their understanding. Doctors are only for things that are alive. Cars are not alive. A car doctor is called a mechanic. Each of these pieces of information allowed them to augment their understanding. The result was learning.

In order to develop understanding, we have to find ways to connect new information to things we already know. For example, let’s say that I know that high blood pressure can increase my risk of developing diabetes. My doctor tells me that sodium intake affects blood pressure. So I can reasonably conclude that reducing my salt intake can lower my risk of developing diabetes. Maybe I reduce the amount of salt in my diet, and my blood pressure does go down. So I’ve instilled a belief now. I’m healthier because I’ve made that one dietary change, and I’m less likely to develop diabetes.

But now what happens when I encounter contrary evidence? Maybe someone tweets a link to a news story saying that the benefits of reducing salt are overstated. Or maybe there’s a doctor who writes an article about how reducing sodium tends to increase fat and sugar, which cause more harm than the sodium. Or I see a Facebook post about the restorative power of sea salt.

If my belief in the link between sodium and diabetes is strong enough, I will just reject this new information. There’s no way to fit it into my existing understanding. These people must be crazy. I start questioning their credibility. I look for ulterior motives. I start trying to find flaws in their research or reasoning.

If I’m already convinced that sodium and diabetes are linked, then I embrace evidence that supports that belief, and reject evidence the contradicts that belief. In order to change my mind, you have to find a way to attach new information to my existing understanding that doesn’t contradict everything I already know. Maybe you could point out that most people who have diabetes also have high blood pressure, but that millions of people with high blood pressure don’t develop diabetes. As it turns out, diabetes may be a contributing factor to high blood pressure, not the other way around. Or maybe you can find other examples where correlation does not imply causation, and plant a seed to restructure my understanding of diabetes and blood pressure.

But ultimately, you’re not going to be able to convince me that everything I know is wrong. That would require me to admit that I’m a fool, and I’m not willing to do that. But on the other side of the coin, I have to be aware that the lens through which I see the world is shaped by my experiences, my beliefs, and the understanding that I have built. And because my lens is different from your lens, our views of truth and belief and reality will necessarily be different.

Just knowing that, though, gives us hope. Recognizing that we have different perspectives, and that I might only be right 90% of the time instead of 100% of the time, means that there’s now room in my lens for contrary ideas.

When I was a boy, world was better spot
What was so was so, what was not was not
Now, I am a man, world have changed a lot
Some things nearly so, others nearly not

There are times I almost think
I am not sure of what I absolutely know
Very often find confusion
In conclusion, I concluded long ago

In my head are many facts
That, as a student, I have studied to procure
In my head are many facts
Of which I wish I was more certain, I was sure
Is a puzzlement

Image Credit: Knowledge Sharing by Ansonlobo on Wikimedia Commons
Lyrics Credit: A Puzzlement, by Oscar Hammerstein II

I should point out, by the way, that as far as I know, high blood pressure does not cause diabetes. Also, in my own experience, reducing sodium does not cause a decrease in blood pressure. Your mileage may vary.