True Belief

As Chucky says, there are some beliefs that as a pragmatic matter, we treat as certain. Maybe we're actually living in a computer simulation, or it's all a dream, but there isn't anything to be gained by even bothering to think about that. We navigate through spacetime assuming that the immediate apprehensions of our senses are generally accurate. The familiar objects around us are really there, the ordinary processes of cause and effect work,  the sun is in the sky . . . 

There is another category of belief that I am quite certain about. I do not apprehend with my senses directly that the earth is approximately spherical (diameter slightly greater at the equator than pole-to-pole), that it rotates, producing the illusion that the sun, moon and stars move across the sky, and that it revolves around the sun, which is actually a star but it's only about 91.5 million miles away instead of multiple light years. I am quite certain that the earth is about 4.54 billion years old (exactly when the molten blob qualified as "the earth" is perhaps a judgment call) and that all life on earth evolved from a common ancestral cell that existed at least 3.7 billion years ago.

Note that although I am quite certain of every assertion in the previous paragraph, nobody believed most of it until quite recently in historical times. The ancient Greeks new that the earth was approximately spherical and Eratosthenes measured its circumference quite accurately in about 240 BC. Copernicus figured out that the earth revolves around the sun, but he kept it a secret until just before his death in 1543, and it took a while before people generally came to believe it.  Darwin published On the Origin of Species in 1854, but it wasn't until the 20th Century that the age of the earth became known, along with the mechanism by which the sun shines, and the mechanism of heredity, and the theory of evolution became plausible and then generally accepted.

Note, however, that there are people who do not believe some or any of this. I'm not sure how many of the flat earthers are sincere, and how many are just goofing, but clearly some really do believe it. And there are a whole lot of creationists who don't buy any of those Satanic lies about the age of the earth, or evolution. How can it be that what I know with absolute certainty some people know, with equal certainty, to be wrong? And why, under the circumstances, am I so confident?

Next time.