I think this related to the “critical thinking” skill that all my teachers always stressed about growing up.

But I still don’t know how to put in useful words what “critical thinking” is because it’s not one thing.

It requires synthesizing a lot of information together in very specific and meticulous ways. And through feedback, collecting your previous thoughts and keeping track of how often you are correct or incorrect.

You can explain critical thinking in many ways but none of it will teach someone critical thinking.

The real trick is that critical thinking is almost always being critical with someone that's trying to mislead you.

Many people try to do it with many different methods. So you're right it's not one thing. Also nobody will teach you all the techniques because they're keeping theirs secret.

Everybody lies.

Critical thinking is one thing but that "thing" is a process rather than an individual item. Critical thinking, like science, is a process that iterates upon itself. You analyze the information you have and make a conclusion based on that information. The "critical" part comes in when you take a step back and then use that same process to analyze your conclusion and poke holes in it, checking to see if the information you have supports that hole or supports the conclusion.

It's like saying that a computer is one thing despite the fact that the one thing is made up of multiple pieces.

I go with critical thinking being thinking about thinking, or meta thinking. Which is to say have a thought, doesn’t really matter what, and then analyse it. Example is throw a dart at the board and then evaluate it compared to your expectations and desires. Feel free to throw a bullseye right away but that’s a different thing. Which is to say, imo, that critical thinking isn’t about being perfect all the time.

I think of Critical Thinking as a closed loop process that aligns a person's mental model of the world with reality. It is just using the scientific method to analyze information in daily life. When done correctly and consistently it is like a really good spam filter against lies and bullshit.