What Does It Mean to Think Critically?

You’re walking down the street and notice the air has suddenly gotten cooler. A dark cloud moves across the sun. You think: it’s probably going to rain. You speed up your steps.

That little chain of thought — noticing something, wondering what it means, checking for evidence, drawing a conclusion — is a tiny example of something philosophers call critical thinking. It’s not just “thinking hard.” It’s thinking that follows a certain pattern: you notice a puzzle, you come up with possible answers, you test them, and you decide what to believe or do.

This article is about what critical thinking really is, why it matters, and what it takes to do it well.

A Famous Philosopher’s Examples

The American philosopher John Dewey (who lived from 1859 to 1952) thought critical thinking was the most important goal of education. He collected examples from real life to show what it looks like.

The Transit Problem. A student is downtown and sees a clock reading 12:20. He remembers he has an appointment at 1:00, an hour’s ride away by streetcar. He realizes he’ll be late if he goes back the same way. So he starts thinking through options: subway? elevated train? Which is faster? Where are the stations? He runs through possibilities in his head, checks them against what he knows about the city, and finally decides to take the subway. He arrives on time.

The Ferryboat Pole. Someone riding a ferry notices a long white pole sticking out from the upper deck, with a gold ball at the tip. At first he thinks it’s a flagpole — but then notices problems with that idea: the pole is horizontal (flags are usually on vertical poles), there’s no rope or pulley for attaching a flag, and there are already two vertical flagstaffs elsewhere on the boat. So he considers other possibilities: is it an ornament? A wireless telegraph antenna? A direction indicator for the pilot? He tests each possibility against what he observes, and concludes it’s probably a steering guide.

The Bubbles. A student washing glasses in hot soapy water places a tumbler upside-down on a plate. Bubbles appear on the outside of the glass, then move inside. Why? He reasons through it: bubbles mean air is escaping. The air must be expanding. What makes air expand? Heat or decreased pressure. Could the air have gotten hotter? He tests his hypothesis by taking some glasses out shaking them (to trap cold air inside) and others holding them upside-down (to keep cold air out). The bubbles appear only on the glasses with trapped cold air. He checks further by putting ice on top of a tumbler — the bubbles reverse direction. He confirms his explanation.

What all these examples share is a pattern: perplexity → possible answers → testing → conclusion. Dewey broke this into five phases:

You get a suggestion — a possible solution pops into your head.
You turn the vague difficulty into a clear problem.
You use one suggestion as a hypothesis to guide your observation.
You reason through what would follow if the hypothesis were true.
You test the hypothesis by experimenting or checking further.

Notice that this isn’t a rigid formula. You might go back and forth, redefine the problem, or suspend judgment when the evidence isn’t clear. The key is that you’re doing something active and careful — not just accepting the first idea that comes along.

What Isn’t Critical Thinking?

To understand what critical thinking is, it helps to see what it isn’t.

Jumping to conclusions isn’t critical thinking. If you immediately accept the first explanation that pops into your head without checking, you’re not thinking critically — you’re being impulsive.

Suspending judgment forever isn’t critical thinking either. If you have enough evidence to reach a conclusion but refuse to make up your mind, that’s just indecision, not careful thinking.

Following an algorithm — just applying a mechanical rule without understanding why — doesn’t count. If you solve a math problem by rote without thinking about whether the answer makes sense, you’re not thinking critically.

Criticizing from an unquestioned ideology also doesn’t count. If you reject every argument that doesn’t fit your political or religious views without actually considering it, that’s dogmatism, not critical thinking.

What Does It Take to Think Critically?

Philosophers have identified three things you need to be a good critical thinker: dispositions (habits of mind), abilities (skills), and knowledge.

Dispositions: The Habits You Need

Dispositions are the attitudes and tendencies that make you willing to think critically. Even if you have all the skills in the world, you won’t use them unless you have the right habits.

Attentiveness. You need to notice when something is puzzling. If you don’t pay attention to the world around you, you won’t even realize there’s a question to think about.

A habit of inquiry. Thinking critically takes mental energy. You need a built-in drive to ask “why?” and to keep pushing until you find an answer. This is probably the most important disposition of all.

Open-mindedness. If you’re already certain you know the answer, you won’t seriously consider alternatives. Being open-minded doesn’t mean believing everything — it means being willing to examine questions even when you already have an opinion.

Willingness to suspend judgment. It’s tempting to grab the first explanation that makes sense. Good critical thinkers are patient enough to hold off on deciding until they’ve gathered enough evidence.

Self-confidence and courage. You need to trust your own ability to figure things out. And sometimes you need courage — because thinking for yourself might lead to conclusions that other people don’t like.

Seeking the truth. If you don’t actually care whether your beliefs are true — if you’d rather just stick with what’s comfortable — you won’t think critically.

Abilities: The Skills You Need

These are the things you need to be able to do, not just be willing to do.

Observing carefully. Noticing details, recording what you see accurately, recognizing when your own observation might be unreliable.

Asking good questions. Turning a vague sense of confusion into a clear, focused question that can actually be investigated.

Imagining possibilities. Coming up with multiple explanations or options, not just the first one that occurs to you.

Drawing inferences. Reasoning from evidence to conclusions. This includes both deduction (if the premises are true, the conclusion must be true) and induction (the evidence makes the conclusion likely, but not certain).

Designing and carrying out tests. Figuring out what experiment or observation would tell you whether your hypothesis is right, and then actually doing it.

Finding and evaluating information. Knowing how to look things up, how to judge whether a source is credible, and when to trust or distrust what you read.

Analyzing arguments. Identifying the structure of someone else’s reasoning — what they’re claiming, what evidence they offer, and whether the evidence actually supports the claim.

Knowledge: What You Need to Know

Critical thinking isn’t a magic trick you can apply to any topic without knowing anything about it. To think critically about something, you need:

Knowledge of the subject. You can’t evaluate a scientific claim without knowing basic science. You can’t judge a historical argument without knowing the relevant facts.
Knowledge of thinking itself. Understanding concepts like “bias,” “evidence,” “hypothesis,” and “inference” helps you do a better job of thinking.
Knowledge of your own mind’s quirks. Humans have predictable weaknesses: we tend to look for evidence that confirms what we already believe (confirmation bias), we remember things that never happened (false memories), and we’re overconfident in our judgments. Knowing about these biases helps you guard against them.

Controversies: What Philosophers Still Argue About

You might think that after all this discussion, philosophers would agree on what critical thinking is. They don’t. Here are a few of the live debates.

Is Critical Thinking General or Subject-Specific?

Some philosophers (like John McPeck) argue that there are no general thinking skills — thinking is always thinking about something. You can’t teach “critical thinking” as a separate subject, they say; you have to teach it within history, science, math, and so on.

Others point out that some abilities — like recognizing when someone confuses a necessary condition with a sufficient condition — seem to apply across many subjects. So maybe there are both general skills and subject-specific ones.

Most philosophers now agree that you need both: general principles of good thinking and deep knowledge of the subject you’re thinking about.

Is Critical Thinking Biased?

Some critics argue that standard approaches to critical thinking favor certain ways of knowing over others — for example, valuing cold logic over emotion, individual reasoning over collaboration, and detachment over personal connection. They worry that this approach can turn students into skilled arguers who are better at tearing down other people’s positions than at understanding them.

Other philosophers respond that good critical thinking already includes empathy, creativity, and collaboration — it’s just that these aspects have been neglected in how it’s taught.

What’s the Relationship to Creative Thinking?

Critical thinking and creative thinking aren’t opposites. In fact, they often work together. Coming up with a new hypothesis requires creativity. Testing it requires critical thinking. The best thinkers use both.

Why Bother?

Why should anyone care about becoming a better critical thinker? Here are some reasons philosophers have offered.

Respect for persons. When teachers and parents give you reasons for their decisions instead of just saying “because I said so,” they’re treating you as someone whose judgment matters. Learning to think critically prepares you to participate in that kind of respectful exchange.

Self-sufficiency. As you grow up, you need to make your own decisions — about school, friends, health, money, and eventually work. Critical thinking helps you make those decisions well.

Democratic citizenship. In a democracy, citizens are supposed to evaluate arguments about public issues — taxes, wars, environmental policies, education. A democracy can’t function well if its citizens can’t think critically.

Understanding the world. At bottom, critical thinking is just a disciplined way of satisfying curiosity. It’s how you figure out what’s really going on — whether you’re washing dishes, riding a ferry, or trying to understand something enormous like justice or truth or the nature of consciousness.

Appendix: Key Terms

Term	What it does in this debate
Critical thinking	Careful, goal-directed thinking that involves questioning, testing, and reasoning before accepting a belief or making a decision
Disposition	A habit or attitude that makes someone willing to think critically
Confirmation bias	The tendency to notice and remember evidence that supports what you already believe, while ignoring evidence that contradicts it
Hypothesis	A possible explanation or solution that you test against evidence
Inference	A conclusion you draw from evidence, which may be certain (deduction) or probable (induction)

Appendix: Key People

John Dewey (1859–1952) — American philosopher and educator who argued that critical thinking (which he called “reflective thinking”) should be the central goal of education. He collected real-life examples of people thinking through problems.
Robert Ennis — A philosopher who spent decades studying critical thinking, identifying its components, and developing ways to test whether students can do it.
John McPeck — A philosopher who argued that there are no general thinking skills — that all thinking is tied to specific subjects. He sparked a big debate about whether critical thinking can be taught as its own subject.
Harvey Siegel — A philosopher who argued that critical thinking is essential for respecting students as persons, preparing them for democratic life, and initiating them into rational traditions.

Appendix: Things to Think About

Dewey’s examples all involve people thinking alone. But much of our real thinking happens in groups — in class discussions, with friends, online. Does critical thinking work the same way in groups? What might be different about thinking critically with other people?
If you know you have confirmation bias (the tendency to favor evidence that supports your beliefs), what can you actually do about it? Is knowing about the bias enough to overcome it, or do you need something else?
Think of a time when you changed your mind about something important. What made you change? Was it a new piece of evidence? An argument someone made? Something you figured out on your own? Did the change feel easy or hard?
Some people say critical thinking is “cold” — that it leaves out emotion, intuition, and personal connection. Others say emotions are part of good thinking (for example, curiosity drives inquiry, and caring about the truth keeps you honest). What do you think?

Appendix: Where This Shows Up

School. Almost every subject involves critical thinking — evaluating sources in history, designing experiments in science, analyzing characters’ motivations in literature, checking your reasoning in math.
Social media and news. Every day you encounter claims that someone wants you to believe. Critical thinking is what lets you decide whether to accept, reject, or suspend judgment on those claims.
Arguments with friends. When you disagree with someone, you can either shout past each other or try to understand each other’s reasoning and figure out where the disagreement really lies. The second approach is critical thinking in action.
Your own decisions. Choosing what to believe about a big issue, deciding who to trust, figuring out what to do in a difficult situation — all of these involve the same pattern Dewey described: noticing a problem, considering possibilities, testing them, and reaching a conclusion.