Are You a Good Critical Thinker?
A critical thinker reasons efficiently to useful truths and effective actions.
Posted April 23, 2017
The state of critical thinking today is no laughing matter - but let's start with some jokes anyway. They're bad but they contain more than a grain of truth. How is critical thinking like driving and sex? Everybody thinks they're really good at it. How do you identify bad thinkers? Just look at all those people who disagree with you about politics!
There's general agreement that there's a crisis in critical thinking today.1 But there's no agreement about what critical thinking is. I'm going to offer a proposal (based on Bishop & Trout 2005). And then I'm going to give you an unscientific critical thinking quiz, a quiz I would have failed before I started doing research on this topic.
What is critical thinking?
Philosophers distinguish theoretical and practical reasoning. Theoretical reasoning is when you think about the way things are. Here, you reason well when you reason efficiently to true and useful beliefs. Practical reasoning is when you think about what to do. Here, you reason well when you reason efficiently to effective actions.
There's a lot more to say about what counts as efficient reasoning, useful truths, and effective action. That's why we philosophers write books about this stuff! But if we stick to common sense, we end up with a simple philosophy.
A good critical thinker reasons efficiently to useful truths and effective actions.
This philosophy has a destructive, critical side as well as a constructive, positive side.
The Destructive Side: Some people identify critical thinking with a single habit, trait, or skill. We can criticize such views by showing that this habit, trait, or skill doesn't always help you efficiently reason to useful truths and effective actions. For example:
- "A critical thinker questions everything." It's unwise to try to question everything - except as a philosophical exercise or as an effort to annoy people. A good critical thinker doesn't question everything. She asks the right questions - questions that lead to useful truths and effective actions.
- "A critical thinker always reflects on problems." It's impossible to reflect on every problem you face. And it's unwise to try. ("Should I get out of the way of the speeding truck? Hmmm.") A good critical thinker uses reflection wisely - to help her arrive at (you guessed it!) useful truths and effective actions.
The Constructive Side: To become a better critical thinker, we need to identify and implement good reasoning strategies - ways of thinking that efficiently yield useful truths and effective actions. Needless to say, this is a massive undertaking. In future posts I'll try to put this constructive project to work. For now, let's turn to you.
An unscientific test of your critical thinking skills
Decades of research in psychology show that good critical thinking seldom comes naturally. It takes effort. But effort isn't enough. As my soccer coach was fond of saying, "Practice doesn't make perfect. Practice makes permanent. Perfect practice makes perfect." But too many of us don't think we need to improve our critical thinking skills. Here's an unscientific test of your critical thinking skills. My answers - which I came up with only as a result of studying critical thinking - are in the footnotes. See if you come up with the same answers; and then judge the answers for yourself.
- 5% of people in your age and health cohort have disease D. Your doctor gives you a test for D that's 80% accurate, and you test positive for D. What are the chances you have D? (To say the test is 80% accurate is to say that if you have D, 80% of the time the test will say you have D and 20% of the time it'll say you don't; and if you don't have D, 80% of the time the test will say you don't have D and 20% of the time it'll say you do.)2
- On January 1, the HIV rate in Palookaville was 1/10,000. On that day, in response to the HIV rate, the city elders implement a needle-exchange program (where drug addicts can exchange used needles for new needles). A year later, thousands of needles have been exchanged. But the HIV rate is up to 1.2/10,000. The city elders call you in as a consultant to evaluate the effectiveness of this program. What do you say?3
These aren't just idle brainteasers. It's important for us to be able to reason well about diagnostic problems ("Given a positive test for cancer or drug use, what are the chances a person has cancer or uses drugs?") and policy questions ("How well is a social policy working?").
An optimistic conclusion
Despite all the doom and gloom surrounding critical thinking, I think the psychological literature offers a hopeful picture. For many practically important problems we face, a good rule for solving those problems is already in our heads. Often, to become better critical thinkers, we don't need to learn a new rule; we just need to more often use the good rules we already know. In future posts, I'll try to convince you to share my optimism.
1. 93% of employers who responded to an online survey reported that their employees' ability to think critically, communicate clearly, and solve complex problems is more important than their undergraduate major. 82% said that colleges and universities should place more emphasis on critical thinking and analytical reasoning (AAC&U Report). In one large-scale study, 45% of students showed no improvement in critical thinking skills in their first two years of college; and 36% of students showed no improvement in their four years of college (Arum & Roska 2011).
2. Not 80%. 4/23 or about 17.4%. Take 100 people in your cohort. You'd expect 5 of them to have D. Give those 5 people the test and 4 (80% of 5) will test positive. Give the other 95 people the test, and 19 (20% of 95) will test positive. 23 people in total test positive for D. Of those 23, only 4 have D. So the chances that someone who tests positive actually has D is 4/23.
3. The city elders haven't given you enough evidence to properly evaluate the program. You want to know what difference the program has made to HIV rates. So you need evidence about both what happens when the program is present (HIV rates go from 1/10,000 to 1.2/10,000) and what happens when the program is absent and all other relevant factors are the same. Without the needle exchange program, would HIV rates have still climbed to 1.2/10,000? Higher? Lower? Without that evidence - in other words, without a control - you don't know what difference the program has made to HIV rates.
Arum, Richard & Josipa Roska. 2011. Academically Adrift: Limited Learning on College Campuses. University of Chicago Press.
Bishop, Michael & J.D. Trout. 2005. Epistemology and the Psychology of Human Judgment. Oxford University Press.