Sometimes it feels as if everyone suddenly wants to think critically, or at least wants schools to teach children how to do it. It appears in curricula, policy documents, vision statements, and endless discussions about so-called “21st century skills,” as if critical thinking were not needed before the 21st century. Teachers are expected to foster it, students are supposed to develop it, and schools are encouraged to place it at the centre of education. Only… what exactly is critical thinking?
A new systematic review in Review of Educational Research shows that this is far less straightforward than it may seem. Jarmila Bubikova-Moan and colleagues analyzed 208 studies on critical thinking in teacher education and reached a striking conclusion: researchers constantly use the term, but often mean very different things by it.
Sometimes critical thinking refers to argumentation. Evaluating evidence, analysing reasoning, and recognising logical fallacies. This is the more classical perspective, rooted strongly in philosophy and cognitive psychology. Think of questions such as: Does this argument hold? What evidence supports it? What conclusion logically follows?
But in other studies, critical thinking meant something much broader. There, it involved critical citizenship, questioning social structures, dealing with power, inequality, and social justice. Critical thinking then becomes almost synonymous with critical action.
And it does not stop there. Other researchers use terms such as reflective thinking, critical reflection, problem-solving, higher-order thinking, and even creativity almost interchangeably. Sometimes, without clearly explaining the differences between them.
Confusing? Certainly. But also scientifically problematic. Depending on which definition is used, what researchers study and what teachers actually do in classrooms can look very different. If critical thinking mainly means logical reasoning, education will focus on argumentation, evaluating evidence, and detecting reasoning errors. If it mainly means emancipation, the emphasis shifts toward social analysis, perspective-taking, and critical pedagogy. And if it simply becomes a generic “skill for the future,” the concept risks becoming so broad that nobody really knows what it means anymore.
The review also highlights another important issue. Many studies never explicitly define critical thinking. Researchers may refer to a famous author, use a questionnaire, or combine several related concepts without clearly explaining exactly what they are studying. That makes it difficult to interpret research findings. If everyone means something different by critical thinking, we may sometimes be comparing apples and oranges.
In that sense, this review also touches on an older debate in education. I have never been particularly convinced by the idea that critical thinking is some universal, context-free “21st century skill” that can simply be trained independently of knowledge. Not because critical thinking is unimportant, but precisely because it appears far more intertwined with knowledge, subject content, and context than popular discourse sometimes suggests.
That debate also appears clearly throughout the review itself. Researchers continue to disagree over whether critical thinking is a general skill or deeply domain-dependent. Can students learn to “think critically” independently of content? Or do they need substantial knowledge in order to ask good questions and evaluate arguments meaningfully?
The authors do not provide a definitive answer, but the debate itself is revealing. Educational discussions sometimes make critical thinking sound almost like a transferable package: a universal skill that can simply be practised regardless of subject matter. Yet much research suggests that knowledge is often a prerequisite for genuine critical reasoning. It is difficult to critically evaluate arguments about climate change, history, or genetics if you barely understand the topic itself.
I have written and said this before: being critical without knowledge often becomes little more than performative scepticism.
Personally, I think one element consistently recurs across the different perspectives: critical thinking ultimately involves careful handling of reasons, evidence, and conclusions. It is about far more than simply “having your own opinion.” In fact, critical thinking often means being willing to question your own assumptions, weigh competing arguments, and sometimes even change your mind.
Critical thinking is not the same as automatically disagreeing with everything. It is not the same as treating distrust as a way of life. And it is certainly not the same as endlessly saying “I’m just asking questions.”
Real critical thinkers do not only question others. They also question themselves.