"Humans are not naturally critical. Indeed, like ballet, critical thinking is a highly contrived activity. Running is natural; nightclub dancing is less so; but ballet is something people can only do well with many years of painful, expensive, dedicated training...

Many people enjoy beer, but very few know much about beer itself. Even people who consume lots of beer typically do not know that much about it. They are, in this sense, unsophisticated beer drinkers.

Of course, there is nothing intrinsically wrong with that. There is no obligation to know the difference between hops, barley, and wort. However, if you do choose to investigate beer, you usually will find that you can appreciate your beer more. Furthermore, knowing about beer will allow you to do things you cannot otherwise do—for example, match beer with food, produce your own beer, or even run your own microbrewery.

Getting into beer is, in part, learning what in an academic vein we might call the theory of beer. You have to learn a new vocabulary, that is, new words and the corresponding concepts, and understanding the concepts means mastering a body of knowledge, including the relevant parts of chemistry and biology. Much the same is true of critical thinking: beyond a certain point, improvement demands acquiring some theory. The serious critical thinker understands the theory of critical thinking. This means, in part, acquiring the specialist vocabulary. Instead of saying, “That argument sucks,” the critical thinker can say that she does not accept the conclusion, even though she grants the premises, because the inference is an example of the fallacy of post hoc ergo propter hoc...

I suggested earlier that college instructors often make the mistake of thinking that they can teach critical-thinking skills by teaching the theory of critical thinking, but the real mistake is not teaching theory as such. The mistake, rather, is to only teach theory or to overemphasize theory relative to practice...

If you like, a bit of theory is like the yeast that makes bread rise. You only need a small amount relative to the other ingredients, but that small amount is crucial for a good loaf. Note also that if you have nothing but yeast, you have no loaf at all.

Is this just stating the obvious? No, because in actual practice, we do not provide students with any, or nearly enough, theory. Most students never undergo any dedicated instruction in critical thinking and stumble through their entire school and college educations without ever learning much about what they are trying to do (Graff 2003). The way we generally go about cultivating critical thinking is to expect that students somehow will pick it all up through some mysterious process of intellectual osmosis."

- Critical Thinking: What It Is and Why It Counts, Peter A. Facione