There are many jokes about their only being two kinds of people in the world. My favorite one is "There are 10 kinds of people in the world: those who understand binary and those who don't."
But in some ways, there really are only two kinds of people. There are the fanatics who are convinced they know the truth and whose minds are closed up tighter than clams, and those who say, "I don't know."
I am the latter. Oftentimes I say "I don't know," and I am just fine with that.
Often, the fanatics are without humor, and cannot tolerate criticism, even if the criticism has poked fatal holes in their beliefs. That's what happens when you think you know the truth. The heretics must be purged!
I always keep in mind that the ideas in our head are not reality. The map (the ideas in our heads) is not the territory (reality out there). Those maps in our heads are never totally accurate, and can always be refined and made better, and sometimes overthrown.
Science, ideally, understands its theories are never totally accurate, are always provisional, and should always be under scrutiny. And when someone appeals to science as some sort of omnipotent and infallible god, that person does not understand science. It's called "scientism" and it's really a religion.
When people say, "I know the truth and how dare you disagree with me!" they are doing this to cover up their own fear and feelings of insecurity. Being convinced you know the truth is quite comforting, since to them the alternative is chaos - in their own weak minds.
I, on the other hand, look at things as a kind of wonder. It's not that I have the truth, but instead am amazed. "There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy."
When people are convinced they know the truth they want to shut down all debate, but without debate and contrary opinions all advancement comes to a screeching halt.
I expect the average semi-retard, who doesn't think much, to not have a particularly open mind. Unfortunately, those who are the cognitive "elite" often put stupid ideas in their minds. The semi-retards, since they really can't think, can only memorize and imitate. That can be a good thing - and it can be a very bad thing.
Unfortunately, many of the "elite" these days are irresponsible with their ideas.
Actually, you can say there are another two kinds in the world: the establishment and the opposition. But then, for all practical purpose, the first are the fanatics and the second say, at their best, "I don't know, so let's go find out."
"There are always two parties, the party of the Past and the party of the Future: the Establishment and the Movement. At times the resistance is reanimated, the schism runs under the world and appears in Literature, Philosophy, Church, State and social customs." - Ralph Waldo Emerson