How to Improve Critical Thinking

Being able to think critically is an essential skill. You need to wade through what everyone is saying and pick out the truth from the nonsense.

Critical thinking isn’t just for detecting fake news, however. You also need it to make accurate decisions. Should you buy a house or rent? Eat paleo or vegetarian? Go to college or drop out and start a company? Each of these decisions is difficult and important, so being able to think critically about them can make a huge difference in your life.

With that said, what’s the best way to improve your ability to think critically?

The Wrong Way to Improve Critical Thinking

I’m going to start with what I believe is the wrong way to improve critical thinking, which is sadly the kind most often taught in schools.

This approach starts by teaching you some basic rules of logical deduction, modus ponens, some examples of fallacies and a whole bunch of Latin terminology that philosophers use.

You work through a few problem sets and, voila!, you’re supposed to be able to reason critically about real-world problems.

While there’s nothing wrong with studying logic and rationality, per se, I don’t think these methods deliver on their intended promise. In particular, there’s a few facts about how our brain actually reasons that make this route to improved rationality a dubious one.

Problem #1: Critical Thinking isn’t a Faculty

The first problem was actually resolved over a hundred years ago by psychologists Edward Thorndike and Robert Woodworth.

The popular view of learning of their day was the idea that human brains contained large, distinct “faculties” such as logic, memory and judgement, and that by practicing them on subjects, regardless of their relevance to the real world, would strengthen these faculties just like lifting weights in the gym improves your muscles.

The problem is that this theory of the mind doesn’t work. The brain isn’t like a muscle. Instead of general, abstract faculties that can be improved with non-specific training, improvements to the mind tend to be extremely specific. General improvements, when they happen, tend to result out of the accumulation of many, many specific improvements, rather than unrelated and general ones.

Consider learning a language. The faculty view says that learning Latin will improve your linguistic faculties. While there’s some benefit of this, most of the work of learning a language is learning specific vocabulary. Thus, if you want to learn Japanese, you’re best off learning Japanese vocabulary—mastering Latin first won’t help too much.

Similarly, critical thinking isn’t just a single monolithic ability that reduces to abstract logical forms. Instead it’s numerous facts, inferences, heuristics and context-specific abilities that must be built up through voluminous exposure to real situations.

Problem #2: Reasoning is Largely Rationalization

The argumentative theory of reason, which I covered in depth here, suggests that the seeming failure of many types of human reason are misinterpreted because they don’t recognize reason’s true function.

Instead of a general-purpose way of making better decisions, reason is a faculty for generating explanations and evaluating those of others. The intelligence comes from throughout the brain, via mostly intuitive modules which are specific and trained through practice, rather than some mystical faculty that does critical thinking.

If this theory is correct, then another reason critical thinking is hard to improve is that we’re mostly not coming up with more intelligent decisions when we think critically, but trying to create more appealing arguments for our positions (or more incisive attacks on the arguments of others).

While this form of critical-reasoning-via-debate has great benefits for our collective knowledge, individually it doesn’t help quite so much. Instead, critical thinking when used alone tends to be more of a tool for justifying your intuitions rather than methodically evaluating them to make better decisions.

The Right Way to Improve Critical Thinking

So if the classic view of critical thinking is wrong, what’s the right way of doing it?

I think there’s two broad approaches that will work to make better decisions:

1. The first is creating a context that will lead to better decisions, in light of what we know about human reasoning already.
2. The second is to absorb lots and lots of knowledge about the world and integrate it through practice making decisions—in other words, critical thinking comes from being smart.

Strategy #1: Creating Contexts that Enable Smart Decisions

This first strategy is to recognize what you’re actually doing when you’re reasoning about things and uses this knowledge to try to avoid making common mistakes. Given what we know about how reason works, there’s a few things you can do:

1. Examine the decision in multiple times, places and moods.

Since reason tends to be more to justify than to generate the right judgement, one way to avoid making mistakes is to reason about the same problem in a lot of different contexts.

The modular theory of mind says that rather than a single coordinated function, the brain consists of a lot of semi-autonomous modules that all “vote” their preferred action into the brain. Depending on which module is more strongly activated by the context around you, its vote will get higher weight. So if you’re hungry, scared, angry, sleepy, joyful or sad you may get different inputs into which decision is correct.

Therefore, reasoning about a decision in multiple moods, places and settings will give you the greatest variety of backdrops to reason about things. If the decision is the same each time, you’re can be more confident that you have the correct assessment.

2. Talk to more people and have more debates.

The argumentative theory of reason suggests that reason doesn’t work very well alone. However, it does work brilliantly when combined in public debate. Many well-known problems of human reasoning disappear once you get a group of people together and let them talk about it.

Discussing your decision or judgement with others is a good way to see your ideas refuted or let stronger ideas win the day. Although there’s a risk of group think and conformity pressures, if you take a large and diverse enough group, you’re more likely to be exposed to the best reasoning, which will tend to win out over the majority opinion.

3. Don’t stake your reputation on your choice.

One of the biggest challenges to overcome in critical thinking is that you may not properly update your beliefs in the face of new evidence. Old beliefs may cling stubbornly to their prior position, even once you’re shown to be wrong.

Part of this may be because, in an argumentative theory of reason, we are trying to justify our intuitive beliefs rather than argue against them. Therefore, if you’re only looking for why you’re right, you naturally ignore why you’re wrong.

However, another big part might be the social consequences of flip-flopping on your position. If your reputation and identity is staked on an idea being right, you almost certainly won’t update sufficiently when you’re exposed with reasons that undermine your views.

I’ve tried to counter this tendency in myself by writing about when I’m wrong. By sharing these inversions of beliefs, I’m hoping to separate myself from the content of my ideas, so that I can discard the ones that don’t work, rather than cling to them for fear of looking foolish.

Strategy #2: Be Smarter and Know More

The second approach to improving critical thinking which actually works is to simply learn more about the world. The more you know about things, the better you can reason about them.

I recently had an experience of this when someone told me that they were worried the wifi signals from their phone might cause cancer.

I explained that this doesn’t make any sense. Wifi signals are microwave radiation (and phenomenally low power). Cancer is caused when DNA is damaged. For that to happen, radiation needs to be energetic enough to break molecular bonds. Ultraviolet radiation is strong enough to do this (which is why you should put on sunscreen), but visible light is not (which is why you don’t need sunscreen indoors). Microwave radiation is an even lower frequency than that, so it can’t cause cancer.

The problem wasn’t that this person didn’t have good critical thinking skills. It’s not unreasonable to assume a new technology might have unstudied consequences (including causing cancer). If you heard this from a friend who you think is pretty smart about other things, that’s not a terrible way to make a decision about the risk.

The problem instead was that this person didn’t know enough about electromagnetism to see why this claim didn’t make any sense. If they did, they should be much, much more worried about all the lightbulbs outputting higher-frequency visible light at higher power every day than the faint beam of microwaves put out by the phone.

Critical thinking, therefore, doesn’t happen because you’ve studied some abstract logical form and come to valid deductions. It happens because you know enough about how the world works to rule out certain possibilities as being unlikely or impossible.

The downside to this is that it means critical thinking can’t just be picked up by taking a few credits in college. It means you need to be learning constantly, about all subjects, in order to make intelligent decisions.

The upside is that it also means much smarter decisions are possible. Far from just being an abstract faculty you either have or you don’t, critical thinking is part of the process of knowing things to begin with, and that you can get better at it by learning more throughout your life.