There are many ways to classify knowledge, but, in the end, what each of us knows is based on one of two methods… and sometimes a combination of both.

The first way of knowing is through observation, including experimentation and evidence-based and peer-reviewed knowledge gathered by others.

The second is belief based on faith.

Now, admittedly, if I accept the conclusions or findings of a historian or a scientist, there is an element of faith in the individual and the field, and sometimes a great deal of faith is required, especially if it’s a field with which I have little experience. In science, however, virtually all theories and findings are scrutinized by a great number of other scientists, as are the facts employed, the various kinds of supporting evidence, and the methodologies.

So… when someone says, “I don’t believe in global warming,” or “in human caused global warming”, or “I think vaccines are more dangerous than the disease,” that belief isn’t based on knowledge, but on belief… and upon the conviction that they are right against the weight of evidence and expertise. Now, as science has advanced, some older theories have been modified, and a few even disproved, but in the last century, very few of the current theories have been disproved outright, although a number have been modified or extended as technology has made it possible to test theories and theorems to greater extents.

I’ll also make the point that, at least so far, in areas where science and religion have conflicted in the material world [I’m not discussing the metaphysical world], religious faith has an abysmal record as far as being accurate.

As an interesting aspect of the fact/belief conflict, a recent article in New Scientist pointed out that, after massive river floods in Europe over the past millennium, after two generations, people went back to building houses and structures in the areas that were bound to be flooded – generation after generation. The study concluded that once those people who had suffered the devastations died off it only took another generation or two before their descendants disregarded the historical accounts. The study authors also suggested that the same lack of first-hand experience might explain why there is now a growing number of anti-vaxxers in the U.S. – because these individuals have no personal experience of the ravages of “childhood diseases.

I’m old enough to remember those diseases. I had contemporaries who suffered through polio and who ended up wearing leg-braces and/or in wheelchairs. A young woman I knew was born without a lower arm because her mother had measles when pregnant. Someone in my family had severe vision damage from measles. My uncle died from long-term complications from strep. And even now, over 1,100 children have died from measles so far this year in Madagascar.

Yet we have people in the U.S. who absolutely know that measles is a comparatively harmless childhood disease.

So… why do some people insist on holding to beliefs that are proven inaccurate? Is it because those beliefs are so central to their religious faith or their self-image that they cannot accept something that goes against facts and evidence? Or because they cannot believe something that goes against those beliefs unless or until they personally experience something drastic that changes those beliefs? Or because changing or adjusting their beliefs will alienate them from their faith or “tribal affiliation”? Or because they just have to be “right”?