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Wittgenstein’s Ruler: How to Not Be Fooled by Authority

Award shows are a double-edged sword. For the average spectator, it can be difficult to tell whether the winner truly deserved the recognition, or if the judges who made the decision were just profusely biased and incompetent. In the latter case, the award tells us an awful lot more about the judges than about the person being judged; albeit unintentionally. It’s a textbook case of Wittgenstein’s Ruler, an indispensable cognitive tool for critical thinking. Here’s what it is and how we can use it to avoid being fooled by a seeming authority.

What Is Wittgenstein’s Ruler?

Wittgenstein’s Ruler states that “unless you have confidence in the ruler’s reliability, if you use a ruler to measure a table you may also be using the table to measure the ruler.” The philosophical concept was coined by essayist Nassim Nicholas Taleb in his book Fooled by Randomness. Named after Austrian philosopher Ludwig Wittgenstein, it challenges our assumptions about people and their judgements. Here’s the adage in full context:

Unless the source of a statement has extremely high qualifications, the statement will be more revealing of the author than the information intended by him. This applies to matters of judgment. According to Wittgenstein’s ruler: Unless you have confidence in the ruler’s reliability, if you use a ruler to measure a table you may also be using the table to measure the ruler. The less you trust the ruler’s reliability, the more information you are getting about the ruler and the less about the table.

Nassim Nicholas Taleb

In other words, Wittgenstein’s Ruler is not about measuring an object. It tests our assumptions about the world, including the accuracy of the measurement tool itself or the amount of faith we have in the authority using it. If we consider the award show judges to be highly credible, we’ll have confidence in the merit of the awards. The less we trust the jurors, the more we learn about their motivations and politics as prizes are handed out.

Applications of Wittgenstein’s Ruler

Beyond award shows and in everyday life, there are a variety of applications of Wittgenstein’s Ruler. In fact, you may end up seeing it everywhere:

  1. A scientific study is only as good as the validity and reliability of the underlying methodology. A badly designed experiment and results that reek of Cargo Cult Science reveal more about the researchers’ integrity than they tell us about the subject of study itself.
  2. The credibility of a performance review hinges on the metrics used to assess the employee’s work. Standards that seem arbitrary will tell you more about the people who designed and implemented them than they tell you about your actual work performance.
  3. The less confidence you have in an English language assessor evaluating your speaking skills, the more the results tell you about the interlocutor. Your terrible scores could be an indication that your teacher unwittingly assessed your ability to decipher her cryptically worded tasks instead of your language abilities.
  4. Or take an authority in the field of financial advice who promises you a 10% monthly return on your $10,000 investment. Inadvertently he gives away more information about the quality of his “expert advice” and his business practices than about the prospects of the stock market.
  5. Finally, consider a Brazilian jiu-jitsu black belt who keeps being submitted by absolute beginners. You learn very little about your fellow white belts. But an awful lot about the grading standards of the black belt’s gym.

In all five cases, applying Wittgenstein’s Ruler prompts a careful evaluation of the methods, metrics and people involved in making the judgements. That is unless we have the highest confidence in our researcher, supervisor, teacher, financial advisor or BJJ practitioner. In this case, we’d accept the results and have no second thoughts about the people and criteria involved. Whether our trust is justified or not.

Breaking Down Wittgenstein‘s Ruler

To understand Wittgenstein’s Ruler more deeply, three concepts seem relevant: relationships, reliability and heuristics.


Psychologist Paul Watzlawik was famous for coining the four axioms of communication. The most famous one is probably the notion that “you cannot not communicate” as even silence sends a message. His lesser-known second axiom seems relevant when it comes to Wittgenstein’s Ruler:

Every communication has a content and relationship aspect such that the latter classifies the former and is therefore a meta-communication.

Put differently, we interpret the content of a statement within the context of our relationship with the sender of the message. For example, the sentence You’re such an idiot! can come across as either insulting or endearing. It depends on whether we’re being informed about our idiocy by a complete stranger or by someone close to us whom we trust.

Similarly, when applying Wittgenstein’s Ruler we don’t take a statement or judgement at its face value alone. We also evaluate it based on our relationship with the other person. The less trust there is between us, the more we look beyond the words being said. Our relationship effectively determines the additional content of the message.


But how do we know we can trust a source as reliable? One way to look at it is through the lens of consistency. “It’s the most difficult thing in the world,” according to Andrew Bustamante. The former spy argues: “When you have someone who performs consistently over long periods of time under various levels of stress, you have high confidence that that is the person that you can trust.”

To earn trust we have to perform almost unfailingly well. Since it requires extraordinary objectivity, expecting consistently valid and reliable judgements from a human is a big ask. Add to this all the biases and preconceived notions we may have towards an individual and you end up with a handful of people to whom that trust applies. If you’re lucky.

What I’m getting at is that it’s hard to think of a scenario in which Wittgenstein’s Ruler doesn’t apply to some extent. In matters of judgements, even the most credentialed thinkers and doers run the same unreliable operating system in their brains. That brings us to the problem of keeping track of their performance, which happens intuitively.


Trust in someone as a reliable source is hard to quantify. It seems to be a matter of instinct. Psychologist Daniel Kahneman popularised the distinction between system 1 and system 2 thinking. System 1 is the fast and intuitive, instinctive and emotional part of our brain. System 2 on the other hand is slow and deliberate, analytical and rational.

According to Kahneman, having “intuitive feelings and opinions about almost everything that comes your way” is “the normal state of your mind”. Knowing nothing about tennis, you sense which player is going to win. Having never met them, you trust or distrust people instinctively. The use of such unconscious heuristic judgements as a guide for our behaviour is a unique human strength.

These simplifications, also known as mental shortcuts, allow us to process the vast amounts of information we encounter every day. About our environment, the hidden relationship aspects of a message or other people’s reliability when it comes to giving out awards. The idea then is to trust your instincts when it comes to the reliability of a source and detecting Wittgenstein’s Ruler situations. However, this approach is not without flaws.

Wittgenstein’s Ruler and Critical Thinking

Heuristics are no substitute for critical thinking. While some are superior to logical reasoning, they can also lead to poor decisions. As opposed to heuristics, critical thinking is a deliberate process of cognition and metacognition. The goal is not only to come to a judgment. But also to improve the quality of your thinking in the process.

So once the intuitive part of our brain has done its job of detecting a potential baloney statement, it’s worth handing it over to the rational part of our brain to assess the accuracy of the information. But not just the information we got about our “table”. Also, the additional one we gathered about our “ruler”. For example, using a third reliable reference point or multiple sources to evaluate its credibility can do the trick.

Beyond that, it wouldn’t be a critical thinking exercise if we didn’t examine our own beliefs and assumptions. This includes the suitability of the decision-making tools we’re using ourselves; the methods we use when passing judgment onto other people’s judgements. Our personal “rulers” so to speak. Such critical thinking skills are an essential part of the Five Habits of the Master Thinker, which I unpacked in a previous essay.

Finally, let’s help our award judges out by suggesting a collaborative way to question their assumptions and decisions. Premortem Analysis is a great way to question your own assessment of a situation. Shortly before the decision is finalised, jurors would pause and assume their pick would turn out to be spectacularly wrong. Then they ask themselves what went awry, what that tells them about the way they came to their judgement and how to fix it.

Closing Thoughts

Wittgenstein’s Ruler is a useful tool for situations where we don’t know the full extent of our ignorance. For navigating uncertainty in a world where we’re constantly bombarded with information and often don’t know what to believe. By acknowledging our own limitations and using reliable tools to guide us, we can make better decisions and more accurately understand the world around us.

In applying Wittgenstein’s Ruler we not only avoid being fooled by a seeming authority. We also avoid fooling ourselves. Taleb goes even one step further, saying: “The ONLY test of intelligence that counts is to see if the person detects Wittgenstein’s ruler situations.” The more ludicrous that award show turns out, the more we should feel the urge to scrutinise the whole event. Or perhaps question our own sanity for watching it.