Most college courses include “critical thinking” as a desired learning outcome. But what do we mean by the term? And why is it so important—for coursework and for life?

“Critical” is derived from the Greek word krisis, which means “to separate.” When we think critically, we are pulling things apart to evaluate them, but we are also separating ourselves from our thinking (our interests and biases) to be better thinkers. 

Sometimes that is easier said than done.

Let’s take something easy to digest: sports. It’s easy to have a favorite team. Mostly, loyalties come from who your family favors and where you grow up. You can root, root, root for the home team, but if you are going to make a claim that any one team is better than another, you’re going to have to back it up with evidence. 

There is a big difference between saying (1) the Cubs are the best team in baseball and (2) the Cubs are the best team in baseball because they had the best regular season record and went on to win the World Series. (Yes, that really happened.) Critical thinking can be directed toward others, but we need to be the most critical about our own views.

Very quickly, however, invoking statistics (win-loss record, runs scored, etc.) becomes a discussion of the relative merit of one piece of evidence over another. The classic example of this is batting average, which was for far too long exaggerated. On-base-percentage (which also takes into account walks and being hit by pitches) is a much better measure of a hitter’s skill. 

In academic settings, critical thinking is more than just remembering or understanding content or offering an opinion. It’s an essential skill that requires analyzing and evaluating theories and evidence; identifying biases and challenging assumptions; considering the consequences of hypothetical or counterfactual situations; developing new and probing questions; making informed decisions about complex problems; and applying knowledge to a new field or area and even creating new knowledge. 

A great example of critical thinking is Lorenzo’s Oil. The 1992 film documents the true story of Augustos and Michaela Odone as they attempt to find a cure for their son’s adrenoleukodystrophy (ALD), a fatal disease. The cure they discover, a combination of rapeseed oil and olive oil, is counter to the established medical wisdom of the time and resisted by most experts they consult. They eventually have seek help abroad to have their cure manufactured, and it ends up adding 20 years to Lorenzo’s life.

Critical thinking is almost always radical because it goes “to the root” of things, which is why it is so essential to problem solving. Karl Marx, rather cynically, alleged that people can only see a problem once a solution is available. A more optimistic, if idealistic, version comes from John Lennon (from “Watching the Wheels”), where he sings, “there’s no problem, only solutions.” Marx and Lennon were both critical thinkers, but Lennon wrote better songs.

Critical thinking is not always creative, but thinking critically is essential to the creative process, if by creativity we mean seeing things in a new light. Steve Jobs was a great critical thinker. “Sometimes when you innovate, you make mistakes,” he said to The Wall Street Journal in 1993. “It is best to admit them quickly, and get on with improving your other innovations.” For him, trial and error were essential, but so too was not letting biases stop him from throwing an idea overboard.

Some people might be more naturally critical and independent thinkers, but everyone can improve their thinking. We especially need to be mindful about the undue deference we give to both experts and what is commonly held to be right or true. Social conformity and tradition are powerful obstacles to critical thinking.

Even though our aim is more than content knowledge, knowing something is the first and most important step to critical thinking. We need to get in the habit of reading extensively and carefully and then giving ourselves enough time to know what it all means.