Karsten Miermans
Foto | Elwin Rijken
20 Min.


Was fasziniert Sie am kritischen Denken, Herr Miermans?

Von Sabine Walter

Unsere Welt ist komplex und sehr schnelllebig. Wir erhalten jeden Tag eine Fülle von Informationen und müssen teilweise in Bruchteilen von Sekunden Entscheidungen mit Tragweite treffen. Wie uns kritisches Denken dabei helfen kann, was genau sich dahinter verbirgt und wie wir es erlernen und trainieren können, das erklärt uns Karsten Miermans von der Ludwig-Maximilian-Universität in München.

Da wir das Interview in englischer Sprache geführt haben und auch im Original und in voller Länge veröffentlichen, lesen Sie nachstehend die Zusammenfassung der wesentlichen Aussagen:

  • When we practice critical thinking, we try to recognize logical fallacies and to prevent them in the future.
  • Most people do not study thinking as a skill. That is why biases can propagate into systemic biases. This can lead to large consequences in companies or countries.
  • Complexity, dynamism, information overflow and the fact that we can do something about the problems we see, make it useful to master critical thinking.
  • Listen to your gut feeling is not the best way to make decisions. You should listen to it but also be aware when your gut feeling is wrong.
  • If you focus too much on being logical, you might miss out on crazy new ideas and having connections to people.
  • Harry Potter and the Methods of Rationality.” is a good book to get familiar with critical thinking.
  • If you want to start practicing critical thinking, pick a small unemotional case study where all the facts are known and where there’s an answer to the problem.

What exactly is critical thinking?

I have quite a long answer to this question, but the basic summary is that critical thinking is all about becoming a more rational and objective human being. 

Let’s look at this from two sides: logic and cognitive biases.

Let’s start with logic. We’ve all probably once had that experience of realizing that we made a circular argument. The last few decades of research and psychology show that people do this all the time. We as humans very often show these logical fallacies. When we practice critical thinking, we try to recognize logical fallacies so we can prevent them in the future. That’s one part. The more subtle part — more interesting but also more difficult — is that of cognitive biases. Cognitive biases are typically mental shortcuts, sort of mental tricks that make it easier for our brain to deal with very complex topics and information. And a great example is the so-called “sunk cost fallacy”. Have you ever heard of sunk cost fallacy?


It’s quite fascinating. What turns out is, that after we’ve invested time or money in something, we cling to that thing even if it’s better for us to stop investing.

Could you give us an example, please?

There are various examples. Let’s look at a situation out of nearly everybody’s life: Suppose you are a light eater. You go to a restaurant and you get a big plate of food. Even though the meal is too large, you continue eating after you are full. Otherwise it would be a waste of money. This is an example of the sunk cost fallacy on the personal level.

There are also examples on a much bigger scale with much bigger consequences. I’m from The Netherlands. And in the Netherlands, we participated in the Joint Strike Fighter program. This is a program with the UK, United States, Norway and some other European countries to develop these hyper modern, very powerful fighter jets – the F-35. This program started many years ago and the cost of this program kept rising and rising over the years. But even though this was costing the Dutch government billions of euros and, after some point, it would be cheaper to buy a different fighter jet that was just from a different company or different government, we did not cancel the program. And neither did the US government. This was a 400 billion dollar program. So, also many people in the US called for a cancellation but it never happened.

Of course, this is a very complex topic, but I think it’s pretty likely that on many levels “sunk cost fallacy” was at play here: the various governments did not want to lose their investment even though it might have been less expensive to stop the project and accept the loss of the initial investment.

So, you say, if we would apply critical thinking, we would stop those projects.

In some cases, exactly. And we would recognize more easily that there are many such mental shortcuts – cognitive biases – that affect our thinking. Critical thinking is about recognizing these biases to finally overcome them.

What exactly captivates you about critical thinking?

Personally, I just find it interesting the way our brain works. 

But if you don’t find human psychology as interesting as I do, then let’s ask the following question: what are possible consequences a lack of critical thinking can have? 

Let us again address that question from a personal and a collective perspective. On the personal perspective, these days we have an overflow of information. And we really have the possibility to make a lot of choices how to deal with that information. We’re expected to have well-formed opinions on topics ranging from global warming to immigration to car free zones in the city center. And those are so wide ranging and so complex that you really need critical thinking skills to answer them in a fact based and logical way.

But we don’t really study that as a skill. At least, most people aren’t taught to think. It’s more common in schools to study facts. The act of thinking is usually not a topic of discussion. The necessity of critical thinking for logically coherent, fact-based opinions is an example of critical thinking on a personal level.

We also already discussed an example of a bias (the sunk cost fallacy) on a collective level. With that example, we saw how biases can propagate into systemic biases, where a whole company, government or even country shows irrational behavior. Of course, this can have really large consequences.

So, besides it being fascinating for me, this lack of critical thinking skills can have a major impact on our lives. Once you start to think about it, you start to see it everywhere. There are all these biases in the way that we process information, again both on a personal level but also on a societal level. Let me give you one more example. I gave you the two extremes: personal and collective. But there’s also something in between there. You have companies which consist of maybe ten to a thousand people. That’s not really a whole government or a whole country, but it’s also not a personal level.

There’s this interesting effect with companies that hire new people. That often involves one-on-one interviews. To get a feeling of what the new hire might be like, to see whether this employee fits in the team. And that’s a great idea. But there is this interesting effect called the “halo effect” that can lead to a suboptimal hiring process. The “halo effect” is when we form a good impression of a person based on some set of qualities, and subconsciously believe that this implies that they are good at other, unrelated tasks. An effect is that we forgive or ignore mistakes they have made. This “halo effect” can really distort how you choose new hires.

Biases on a collective level also involve group think, which can lead to strong opposition to innovation in a team. On all these different levels, both personal and collective, you can have these interesting psychological biases that can have large consequences, without you ever realizing that that’s due to such biases.

How does your argumentation fit to the statement: „Best decisions are gut decisions.”?

I don’t really agree with that statement, to be honest. I guess there are two extremes in how you can make decisions: one way is fully going with your gut feeling, intuitive thinking, going by what your first impression is, etcetera … The other extreme is to try and simplify reality by making everything logical and quantitative and mathematical. I believe that neither of these two extremes are perfect. If you try to make every decision logical or quantifiable, there is a risk of you losing important information — your emotions or expert intuition. But these gut feelings can also be treacherous. 

The halo effect and the sunk cost fallacies are examples of when your gut feelings can betray you. There are many more examples of biases like that. I think that you should listen to your gut feeling but also be aware when your gut feeling can be wrong. Does that make sense?

Yes. I think for some people it makes sense.I think there are other theories saying that people who are really connected to themselves can rely on their gut feeling because they perceive so much information – even things you can’t see, feel, touch, whatever… And those who are not 100 percent connected to themselves, they need a very logical approach. But these are different theories which exist in parallel. But I agree that the mixture of it makes it reliable and sustainable for taking decisions.

I agree with your last statement.

You also mention the word “parallel” and I like that word because I think that being connected to oneself and to other people on an emotional level is not incompatible with critical thinking.

I can actually share a funny story here. I first started delving into critical thinking about six to eight years ago. I started reading these books about fallacies and biases and so forth. This made me kind of obsessed with being correct and logical. I tried to be hyper logical and this was decreasing the quality of my personal connection with people. I was always trying to be correct. And if you’re always trying to be correct, you might no longer have space in your head to think: Do I like this person? Is this a pleasant conversation and how can I be of help to this person? Is this a useful idea? … and so on.

So, if you focus too much on being logical at every moment, you might miss out having connections to people or having crazy new ideas. I think it’s good to be aware of these risks. But again, you should somehow find a balance and the balance depends on the situation. Sometimes you have to be more logical and at other times it’s better to form connections with people.

These are different ways of thinking – not necessarily incompatible.

I even think, when you took a decision based on your gut feeling, when you have to communicate your decision and to convince others, it is much more appropriate in our society to base your decision on facts and logical arguments instead of “proving” it with your gut feeling.

Yes. I’d like to comment on that. I think that it is indeed very tempting to first form a gut feeling and then try to find logical arguments or facts that support your gut feeling. Actually, there’s a term in critical thinking for that, as well. It’s called “post rationalization”. You want to do what feels good, but you also want to sound smart and logical. The sunk cost fallacy we talked about before is an example of that. People that work in governments are very good at communicating their point of view and I’m pretty sure that they were able to support their decision with facts and arguments. They used beautiful charts and arguments with complicated statistical data. But the fact that you’re able to communicate a convincing narrative with facts and logic arguments does not necessarily mean that that initial decision was the most logical one. The order is important here: are you using facts before the decision making process, or using facts to support a decision after you’ve already made that decision? The second one is post rationalizing, the first one is a part of making rational, fact-based decisions.

So, I guess communicating with facts is better than not using facts at all. Using facts and logic during your decision making process is a part of rational decision making. There is also research about this. Rapid feedback loops during the decision making process is connected to rational decision making.

But in many companies, feedback loops can be very complex and not very fast. In large organizations, you often don’t really know how your decision impacted something downstream. So, it’s difficult to know, based on the direct consequences, whether a decision was logical or not. And then your gut feeling can really go wrong. This joint strike fighter was an example. We still don’t know the consequences. Maybe in 10 years, historians will analyze it or write a book about it and they’ll know, but the consequences of a decision are definitely not known briefly after the decision was made. So, yes, your gut decision can be really powerful in terms of things that you have real expertise about because you just saw them a thousand times. But if the information or systems are too complex, your gut feeling can be very treacherous and give you a false sense of security. And actually, if you were more logical about it you might have realized it’s very complicated and you should not be so sure about your decision.

Without having studied critical thinking what are aspects of this kind of thinking we automatically do in our day to day life?

Actually, there is a nice bridge from our previous question to this one because you already mentioned gut feeling and intuition. Intuition and our ability to rapidly combine very complex information is incredibly powerful. It can also be betraying. So, combining information can sometimes lead you astray. You might see patterns where there are no patterns; you might form an intuition that’s not accurate. But to actually come up with new ideas, products and arguments it’s not just enough to detect flaws in beliefs. You need to come up with an actual idea. You need to combine information.

How does this work? You need that incredible human ability of recognizing patterns and combining information quickly. People that develop artificial intelligence try to do the same thing. They try to design algorithms that combine information and recognize patterns. It turns out to be not so simple. Recognizing patterns and complex data and combining completely different ideas is one of the things that humans right now are way better at than computers.

To cut a long story short, I think our ability to combine completely different things in our lives and our expertise in a sub-second way, is a very good tool in critical thinking for suggesting new ideas and new hypotheses. And then of course you need to check the validity of them, but you first need to get started with these (crazy) ideas.

Why do you think, for our today’s society it is absolutely mandatory to master critical thinking?

I actually like the question because I agree with the implication of the question: that critical thinking is important for today’s society. There are different reasons:

First, life during, let’s say, fifty to a hundred years ago, was much more static. Our personal freedom was quite limited. Many people lived their whole lives in one and the same village. They did not have the social ability to move away. So, the fact that people did not have so much freedom, to develop their own projects and to shape their careers, to invent new companies, that makes it not so useful to be a good critical thinker. 

Nowadays, we have a lot more freedom. We can indeed set up our own companies much more easily. We can move to a different place, we can form our life. It means that we can apply our thinking skills to real-world issues.

Second, there’s now a lot of information. So, we are both forced to think critically about the information that comes our way, and we have more freedom to deal with that information and to shape the world around us in a much more effective way than at any point in the past.

And we have much more complexity.

Yes, absolutely. And I think also the complexity has led to the dynamism of society nowadays.

So, the complexity and the fact that it’s so dynamic, and also the information overflow and the fact that you can do something about the problems you see, makes it useful to master critical thinking.

What are areas in our life, critical thinking is not appropriate at all?

This is a question that I do not have an answer to, yet.

How do you practice critical thinking?

One thing that I now enjoy doing, is to actively change my mind. Some time ago I used to be my own best friend in terms of my opinions. I would always agree with myself. And now I always try to find the mistakes in my own argumentation. That way, you can try to be your own worst enemy. When you start doing that it’s very uncomfortable. It’s actually very stressful. They even had people do that, like some cruel psychological science experiment. They had people give facts that were in conflict with their ideas. This turns out to be very stressful. People don’t enjoy having their minds changed. But if you practice it enough then it becomes less stressful and after a while it becomes like a fun exercise. This way I’m trying to disprove my own ideas.

That sounds a bit like Paul Arden‘s book „Whatever you think, think the opposite.”.

I actually don’t know this book. But it sounds like a cool complementary tool. You could think the opposite – or you could find flaws in your own arguments. They are a bit different, but they hopefully lead to the same result that you very quickly change your mind, if you had a wrong idea about something.

Do you have another easy exercise for us to practice critical thinking?

It’s not really an exercise but I would start with reading or listening to “Harry Potter and the Methods of Rationality” by Eliezer Yudkowsky. It’s a wonderful book.

It’s fan fiction where Harry Potter grows up to be a wizard, but a wizard that was born to scientist parents. Harry Potter uses critical thinking to explore this crazy wizarding world where magic occurs, and people can transform into animals. He tries to apply the art of rationality to all these crazy things he sees. That’s a great fun way to start.

Before I mention another exercise, I want to point out what I think you should not do. If you want to rigorously improve your thinking skills, it’s really essential to be able to know when you’re correct. That is why I recommend, initially at least, to leave out very fuzzy and emotional topics like religion or ideology. These topics are very broad, so that you cannot tell correct from incorrect easily but also so emotionally charged that your cognitive biases are working against you even more than otherwise. That’s what I think you should not do.

Now, we start with what you should do or could do. It’s much better to start with a small unemotional case study where all the facts are known and where there’s an answer to the problem. And then you can slowly increase the complexity by increasing the details involved or by making correct and incorrect more vague or by increasing the emotional charge.

Concretely, what I would suggest is picking either one cognitive bias or one logical fallacy that you find particularly interesting. There’s a very cool website with a list called “yourbias.is”. Pick one and try to recognize it on the news, for example, or in the newspaper. Only focus on that particular bias or fallacy for a week. Maybe it’s a bit sad to realize this but I think it’s not so difficult because you’ll quickly find out that these biases are present all over the place, for example when you’re watching the news.

That’s exercise number one. Bear in mind, these people are making that bias. This news reporter is having a bias. Once you get the hang of that after a few days ask yourself the question: How could I in this particular case – with all the facts I have – construct an argument that would not suffer from this particular fallacy? Then, you not only practice how to stop mistakes but also how to be able to solve the flaw in the argument. So, you improve the issue. That’s a concrete exercise.

And let me point out one more thing: It is very difficult to become a better thinker if no one in your surroundings is interested in that. So, surround yourself with other people that want to become better thinkers and you will see that it gives an enormous boost in the quality of your thinking. 

Karsten, as you said, critical thinking is about recognizing cognitive biases. Let’s imagine a society where journalists consequently use critical thinking before publishing an article, as Gabor Steingart for example does it.

What would be the impact on our society?

That’s an interesting scenario because we all see politicians use logical fallacies to manipulate people. To an extent, we are now accepting this type of communication. Hopefully, with more critical thinking skills, we would say more often: I don’t want this bullshit story. I want a more fact based argument. And that would be the beginning of a sustainable change.

And if companies would consequently apply critical thinking, what would be the benefit of that?

Things would change step by step.

In fact, I think that many things in businesses need to operate on autopilot. Thinking long and hard about them might cost even more than it helps. In those cases, critical thinking is not useful. But there are also cases where critical thinking would be really beneficial.

One case is when you have rapid changes in complex systems. Another case is when you have the slow creeping in of biases. Realizing the risk of for example the halo effect will not change something from day one, but it will change the group dynamic step by step. Knowing more broadly how to avoid biases in decision making can make leaders avoid costly mistakes because you’re not aware of these biases.

Karsten Miermans is a theoretical physicist and critical thinking enthusiast. He will soon be searching for a new job in the tech industry. This year (2019-2020) he will part-time teach critical thinking to a small group of high-school students. Interested students could contact Karsten and sign in under Karsten’s personal website or under http://lyzeum-muenchen.de/understanding-thinking.
Karsten’s dream is to expand to additional workshops and spread the art of rationality to a broad audience.

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