The term “critical thinking” is a common phrase in the academic community. However, it appears difficult for individuals to agree on one single definition. It is widely accepted that critical thinking is a valuable activity, something we should be encouraging in our students. But, if we don’t have a functional definition of what it is, then how will we know if our students are engaged in it? Knowing what critical thinking is and what it isn’t is important for both teachers and students. Having a working definition allows teachers to recognize and promote critical thinking in students and students to recognize it in themselves. Such metacognitive strategies are useful in that the strategies alert students to the ways in which they are thinking, critically or otherwise. In light of this, let us attempt to discover not only what critical thinking is, but why it is useful.

Defining the Concept

While humans have been engaged in the act of critical thinking for millennia, it wasn’t until the 20th century that the term “critical thinking” itself came into use. Much of how we currently talk about critical thinking can be traced to Edward Glaser’s groundbreaking 1941 study An Experiment in the Development of Critical Thinking. In that study, Glaser identified critical thinking as a habit of using the information one acquires in an intellectually rigorous way to determine one’s beliefs and actions. These attributes of critical thinking differentiate it from the other kinds of thinking we are engaged in on a daily basis.

Critical Thinking: A habit of using the information one acquires in an intellectually rigorous way to determine one’s beliefs and actions.

Thinking can be properly defined as any activity of the mind. Critical thinking, however, involves the examination of knowledge in a skillful manner. Therefore, we can say that critical thinking is not the memorization of information nor the mere exercise of certain skills – for it is one thing to be able to plug numbers into the Pythagorean theorem and quite another to understand how it represents the relationship between the sides of a right triangle. We can synthesize all we have said about critical thinking into the following sentence: Critical thinking is the habitual use of information to solve problems in a meaningful way. Here, “meaningful” is meant in the sense that individuals know what they are doing and why they are doing it, i.e., it has meaning.

Why Be Critical Thinkers?

Knowing what critical thinking is and why it is valuable are two different things. While it might seem obvious that we want students to engage with information to solve problems in a meaningful way, to accept something as an “obvious fact” does not demonstrate our own critical thinking abilities. What reasons do we have to develop the critical thinking abilities of our students?

For one, critical thinking is universal, i.e., it is not subject-specific. A student with advanced critical thinking skills will be able to succeed in any field of study because critical thinking is about how individuals use information and not necessarily the information itself. In addition, critical thinking is constructive. Other thinking methods, such as data memorization, are additive—students acquire a collection of disparate facts that, taken together, compose their knowledge base. Critical thinking, however, is constructive insofar as it requires students to build on what they know by making connections and applications, resulting in further and further exploration of a subject as new problems and questions arise from the answers of old ones. An applicable analogy might be, additive learning is the assembly of a pile of lumber, while constructive learning is the building of a house.