What Exactly Is Critical Thinking?

Everyone applauds the idea of critical thinking, and liberal arts colleges often make their ability to teach critical thinking a key selling point. But no one seems to define what they mean by that term.

As I prepared for the start of classes this fall, I tried to pinpoint the critical thinking skills I really want my students to learn. And as I listened to public debates on everything from tax policy to Obamacare, five essential thinking skills seemed to be missing, again and again. So, based on our dysfunctional national dialogue, here are the "core competencies" I hope to instill in my students:

1. The ability to think empirically, not theoretically. By this I mean the habit of constantly checking one's views against evidence from the real world, and the courage to change positions if better explanations come along. I have great admiration for scholars like Richard Muller, the University of California physicist and global warming skeptic, whose work was heavily funded by the conservative Koch brothers. When new, more comprehensive data from his own research team provided convincing evidence of global temperature increases, Muller changed his mind, and later sounded the alarm about carbon dioxide emissions. Unfortunately, however, much of our public debate on many issues seems to be a clash of theoretical world views, with neither side willing to dispassionately examine the evidence or modify their views. In Congress, the individuals most willing to change their minds – the moderates – have been systematically driven out by more extreme candidates who are dedicated to holding fast to their predetermined positions, regardless of subsequent facts.

2. The ability to think in terms of multiple, rather than single, causes. When you drop a book, it will fall on the floor -- a single-cause event. But most of the interesting things in the world have multiple causes; educational success, for example, is affected by a student's aptitude, but also by the educational achievements of the student's parents, the quality of the school he or she attends, and the attitudes and intelligence of the other students in that school. In such cases, simple comparisons become unreliable guides to action, because the effects of intervening variables haven't been screened out. So, for example, judging a president by Reagan's famous question – "Are you better off now than you were four years ago?" – implicitly assumes that presidential actions are the only variable affecting the economy. This is, of course, nonsense – our globalized economy is affected by a huge variety of factors, including exchange rates, oil prices, the fate of the European Union, the strength of the Chinese economy, and so on. In these situations, we need higher-order analysis that adjusts for these external factors to gauge the true effect of a policy.

3. The ability to think in terms of the sizes of things, rather than only in terms of their direction. Our debates are largely magnitude-free, but decisions in a world with constrained resources always demand a sense of the sizes of various effects. For example, President Obama contends that investments in education and infrastructure are crucial to the nation’s future growth. And it makes intuitive sense that better-educated workers would be more productive, and that repaired highways could transport goods to market more quickly and at lower cost. But Republicans are dead-set against new taxes to pay for these investments. In such a polarized situation, the only way to finance these programs would be to borrow money, and these days much of the government’s borrowed funds are supplied by overseas investors from places like China and Japan. The interest payments on government bonds, then, are a real hindrance to economic growth. The wisdom of these investments, therefore, depends critically on the magnitude of the two effects. How big are the payoffs from investments in education and infrastructure? How much of our debt is owned by foreigners, and what interest rate will we have to pay to them? These kinds of debates cannot be solved by looking only at the direction of anticipated effects, because without quantification, we have no basis for comparison of those effects. In politics and policy, size matters.

4. The ability to think like foxes, not hedgehogs. In his seminal book, Expert Political Judgment, Philip Tetlock followed Isaiah Berlin in distinguishing between hedgehogs, who know one big thing and apply that understanding to everything around them, and foxes, who know many small things and pragmatically apply a "grab bag" of knowledge to make modest predictions about the world. In his study of hundreds of foreign policy experts over 20 years, Tetlock showed that foxes outperform hedgehogs in making predictions, and hence tend to make better decisions. But our current political climate favors hedgehogs, because they tend to be more confident, forceful, and predictable in their views. Mitt Romney's choice of Paul Ryan as a running mate can be seen as an attempt by a fox (Romney) to capture some of the allure and excitement surrounding a hedgehog (Ryan).

5. The ability to understand one's own biases. An expanding literature in psychology and behavioral economics suggests that we are full of unconscious biases, and a failure to understand these biases contributes to poor decision-making. Perhaps the most common and dangerous of these is confirmation bias, the tendency to seek out information in accordance with our previous views and ignore or dismiss information contrary to those views. This undermines our ability to weigh the evidence in an evenhanded manner. Our media culture reinforces this problem, as liberals have their MSNBC, The Nation, The New York Times and think tanks like the Center for American Progress, while conservatives have their Fox News, the National Review, The Wall Street Journal and the Heritage Foundation. In the current world, no one need bear the inconvenience of contrary information.

In general, our public debates are textbook examples of non-critical thinking. But these five traits can provide a foundation for a more enlightened dialogue in the future. And students with these skills will think about their world in a deeper, more constructive way.