What Is Critical Thinking?

As far as I can tell, it is widely agreed that critical thinking is an educational good, a key academic outcome, and even a core academic skill. What is less widely agreed upon is what critical thinking is. This isn’t so much because there is a fierce debate raging in academia about the definition of critical thinking. It is more that the average teacher (or homeschooling parent) may have a difficult time articulating exactly what, precisely, critical thinking is. When it comes to critical thinking, it appears to me that most people are operating on the same standard that Supreme Court Justice Potter Stewart articulated for identifying obscene material: “I know it when I see it.”

However, teaching is easier when you have a really strong idea what, precisely, you are teaching. Accordingly, I would like to offer a framework for defining critical thinking produced by years of experience teaching critical thinking as a debate teacher. In addition, I would like to offer a practical suggestion on how that framework can help educators teach critical thinking.

Not One Thing

The first important concept in defining critical thinking is to abandon the idea that critical thinking will be well defined in a single statement. The things that we call critical thinking are different enough that it makes less sense to offer a definition of critical thinking than it does to offer a useful framework for conceptualizing critical thinking. The framework that I offer here is that critical thinking can be conceptualized as a constellation of interrelated intellectual skills which produces an overall picture we call critical thinking. While the stars in the constellation are many, I’ll offer four primary concepts for the constellation in this article.

Intellectual Comfort with Complexity

Cognitive dissonance is an extremely well studied and well developed concept in human psychology. The American Psychological Association defines cognitive dissonance as “an unpleasant psychological state resulting from inconsistency between two or more elements in a cognitive system”. That is a fancy way to say that we don’t like it when we hold competing beliefs in our mind. If the research on cognitive dissonance has demonstrated anything, it is that contradictory ideas are unpleasant enough that people usually do whatever they have to do resolve the unpleasantness. Most often what they do is simplify their thinking.

The psychological motivation to simplify the world is strong because not only does it protect us from experiencing the unpleasant psychological pressure of holding competing ideas in our heads, it also makes decision making significantly easier.

At risk of mixing a controversial topic into the article, I’ll use the current conflict between Israel and Hamas as an example. We could use many adjectives to describe this conflict, but simple is probably not one of them. However, I can reduce my internal psychological pressure and simplify my decision making if I commit to a fairly comfortable and simple rule-

“Good people do good things because they have good motivations and bad people do bad things because they have bad motivations.”

If I fully commit myself to this idea, then my intellectual tasks become relatively simple. All I have to do is identify the good guy and the bad guy in this situation. The rule then takes care of all other questions. If my “good guy” does something that appears questionable, I can fall back on my rule and rationalize the behavior as good because it came from the good guy. It must have good intent and it must be a good action. On the other hand, if someone points out that my “bad guy” might have fair motivations, I can likewise fall back on my rule and conclude that the intent can’t be good as they come from the villain in this situation.

Can you see how flattening out the issue with my rule about good and bad people makes my decision making easier and my thought processes more comfortable? I know who to support, I need not feel any reservations about that support, I only have to think through the issue once, and I need not be bothered about further evidence to the contrary. And this is equally true with any complex subject. Avoiding realistic complexity can really simplify the space in my head.

While avoiding psychological discomfort does offer psychological comfort and everyone has to do it to some extent just to survive, it also shortcuts more complex thinking which better represents the complexities of the real world. For example “Good people do good things for good reasons and bad people do bad things for bad reasons” doesn’t leave room for more complex ideas that likely do a better job of representing the complexities of the real world such as-

  • No group of people is monolithic. Every group contains members with various motivations, degrees of commitment to group goals, and patterns of behavior.
  • Actions can be motivated by many factors at the same time. It is possible for some motivations of an action to be well intentioned and others ill intentioned at the same time.
  • An act can be motivated by ill intent and still produce positive outcomes and the inverse can be true as well.
  • People are complex and nobody acts in perfect conformity with his or her beliefs. Inevitably those whom we call “good” will make poor or even immoral decisions and those we call “bad” will inevitably make good and moral decisions.
  • It is possible that an act lies somewhere on a scale of good to bad.
  • People are complex enough that the concept of good person/bad person may be a false binary in the first place.

One of the most important intellectual skills in the constellation of critical thinking is teaching students to have a strong comfort level with intellectual complexity. This means teaching students to be patient in seeking for answers, being willing to forego the impulse to immediately resolve all competing ideas, and to leave room to reject false binaries, see issues in finer detail, ask whether contradictions are real or only apparent, and generally conceptualize a complex world in a more complex way.

Ability to Observe Bias (Especially in Oneself)

My wife recently received a pretty humorous email advertisement. The emailer wasn’t trying to make it humorous, but there you have it. The email promised to expose Walmart’s dirty political agenda! Of course, with a headline like that, I had to read on. And how would they expose this agenda? As it turned out, Walmart (and also, all other major booksellers) had refused to put a crucial book with vital information on their bookshelves and wouldn’t let you buy it!

In other words, the author (like 99% of authors) couldn’t get his book shelf space at major booksellers. So Plan B was to get you to buy it out of anger and fear that your shared political beliefs were being suppressed and/or out of curiosity of what Walmart didn’t want you to know. Pretty handy trick right?

One benefit we want from critical thinking is to protect students from getting caught up in these sorts of appeals now and in the future. Which means that one of the stars in the critical thinking constellation is an ability to identify what bias is and how it distorts the consumption, internal analysis, and production of information.

Some years ago I showed students a news story about internet scams that was run by a local news station and asked them to tell me what they thought. What they didn’t know was that the story had been sponsored and, in fact, produced by a company selling protection from online scams.

There were a few students who caught what was going on. They all found it odd that a news station would single out a particular company that could protect against online scams and not mention any others. The majority of students had no idea what was going on and it was pretty fun to see their reactions when they realized that the news story was, in fact, an advertisement.

This is the sort of bias detection that we want students to be able to do. However, not all types of bias detection are equally difficult and this task was relatively easy. Really great critical thinking is fostered in helping students perceive bias when perceiving bias is very difficult. To conceptualize consider the following hierarchy in bias detection difficulty-

  • Easiest- Perceiving bias in people/messages with whom one disagrees (likely to happen anyway)
  • Perceiving bias in people/messages with whom the student is unattached
  • Perceiving bias in people/messages with whom the student agrees
  • Hardest- Perceiving bias in oneself (unlikely to happen without serious training)

A few years ago, during the pandemic, we had our students debate the following resolution: “Governments are justified in legally requiring the vaccinations of citizens.” I had a student who was vehemently opposed to the resolution, but was assigned to argue in favor of it. At first she balked but ultimately did a great job arguing her side. What she said at the end of the exercise was pure critical thinking gold. I don’t have her exact words, but she said something like “At first I thought there was no way that I could argue this resolution, but the more I debated it, the more I began to see sense in the side I was arguing. I still don’t think the government should make anyone get vaccinated, but I realized that there were better arguments on that side than I had considered before.” In other words, she started to get a view of how her pre-existing beliefs had caused her to change the way she sought out, processed, and then represented information on that issue. This self awareness will, hopefully, pay dividends for years as she considers how her personal biases and the biases of others distort how we seek out, analyze, and produce information.

Understanding Assumptions

The next star in the constellation has less to do with critically examining what people say and more about critically examining what people do not say. A good way to conceptualize the idea is to think of it in terms of trilateration. In GPS navigation (and if you are an expert, please excuse my crude understanding and explanation), if one knows their distance from three satellites at any given point, then their location in 3D space can be calculated, thus the unknown location becomes known.

Similarly, we know what people tell us, but we don’t always know the assumptions that produce those statements. Strong critical thinkers are able to trilaterate assumptions by working backward logically from the spoken to the unspoken. This matters because often people only willingly share their most popular or acceptable beliefs and keep less savory or more controversial assumptions further from public view (you can think about arguments in favor of eugenics in the 1930s as an example). On the other hand often we ourselves don’t always understand the assumptions that serve as the foundation for what we say. In either case, the ability to work backward to see unstated assumptions strengthens one’s ability to really understand and critically examine what is being represented. This makes students better communicators, more savvy consumers, and better prepared to fulfill their roles as citizens.

The Ability to Name and Express Complex Ideas

Some years ago I had a student tell me that she wanted to write a speech, but didn’t know what to write it on. Actually, it wasn’t that she didn’t know what to write it on per se, but that she just didn’t have the words to say what she wanted to write it on. So I asked her what circumstances brought up the desire to write the speech, how she felt in those circumstances, what she wanted to change in those circumstances, etc. After about ten minutes of discussing I told her that I thought she wanted to speak about passive aggressive communication versus direct and open communication. I explained what each of them were and she excitedly exclaimed that that was exactly what she wanted to talk about. Then she said something interesting. It was something like, “It’s so interesting. You knew what I wanted to say better than I knew what I wanted to say. How does that work?”

The answer is critical thinking. More specifically it is the ability to name and express complex ideas. Students who can do this sort of thinking are able to think and talk in thin brush strokes. Broad concepts can be expressed with broad language. You can use the word “lie” to express a general concept of dishonesty, but if you want to say deceptive obfuscation then you have to use the words deceptive obfuscation or similarly narrow language. Additionally, if you want to talk about deceptive obfuscation then you have to have thought through the differences between deceptive obfuscation and deceptive silence and active lying and non-deceptive obfuscation, etc. Key to that process is the accumulation of frameworks that allow students to intellectually handle more fine and more complex material. For example, Just War Theory is a set of classical ideas that have had a large influence on our ideas about what is and is not acceptable in war. Ideas such as proportionate response, discrimination between combatant and civilian, humane treatment of prisoners, etc. derive from this theory. Understanding the framework of Just War Theory allows one to both think and say things that otherwise would be difficult to think and say regarding war. The same holds true for understanding the frameworks of impressionism in art, foreshadowing in literature, imaginary numbers in math, textualism in constitutional studies, and so forth.

The result of the accumulation of frameworks, thinking in fine detail, and generally having names for and being able to express complex ideas, is that students are better prepared to interact with the world and the ideas in the world because they can better comprehend and express the complex ideas present in the world.

Developing Critical Thinking

I hope you have enjoyed my sketch of the critical thinking constellation. Certainly there are stars that could be added. Perhaps you have some of your own that you would like to add. But I think these ideas offer a reasonable start.

Moving to practical application I want to offer a relatively simple and practical concept for building critical thinking.

A few weeks ago I was in class and I was arguing against students using a bit that I always enjoy using. At this point the class had been discussing some of the complicated tension that exists between freedom and safety in society. At this point in the discussion, I usually have a strong contingent of students who are heavily favoring safety over freedom. The bit plays out with me telling them that they have really convinced me and it makes me wonder why everyone likes the founding fathers so much given their obvious preference for freedom over safety. I try to really ham it up (what morons! I say). At this point in the discussion a student said (maybe with some frustration) “What are you getting at, Sam?!”

It was an interesting question. It seemed to me like she wanted me to tell her what I was trying to get her to believe so that she could evaluate me and what I was teaching. It seemed not to have yet crossed her mind that maybe I didn’t want her to believe something in particular, and instead just wanted to challenge her thinking.

That is, I think, an excellent concept for building critical thinking. How much is the educator challenging student thinking? In how many ways is the educator challenging student thinking? Is the student asked to primarily agree with the teacher or is the student primarily invited to challenge their thought processes? Is the student asked to justify statements, dig out assumptions, think about how their biases affect their thought processes, define what they mean, use new frameworks, speak more clearly, write more clearly, articulate their feelings, disagree with other students, disagree with the teacher, and generally push their thinking into new territory?

In my experience, you can’t teach critical thinking by explaining it. You have to ask students to do it.


The world our students will enter will demand a lot of them. Every tool we can give them to deal with it matters, and critical thinking more than most. For the sake of those students, I hope the reader will find the concepts contained in this article as helpful in building critical thinking skills as I have.