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Top 25 Interesting Ideas and Concepts Everyone Should Know

How do I guard myself against the Chewbacca Defense? What is the Peter Principle? And why should I avoid the Streetlight Effect? The world is full of such interesting ideas and concepts. If we know and understand them, we can navigate life just a little bit better. I’ve spent the past year collecting and writing about the most interesting ones from the world of critical thinking, philosophy, decision-making and storytelling. Some I’ve discussed in-depth on the blog, others you’ll find in my free weekly newsletter featuring 3 Ideas in 2 Minutes.

Top 25 Interesting Ideas

I’m going to give a brief explanation for each of the interesting ideas and link to relevant posts or newsletters if you want to find out more. Here are my Top 25 interesting ideas, concepts, principles and eponymous laws that everyone should know. Plus, there will be a big surprise in the end. Let’s get started.

1. The Peter Principle

In a hierarchy every employee tends to rise to his or her level of incompetence.

Competent people are promoted until they find themselves in a position that exceeds their abilities. The work in an organisation is done by those who haven’t reached their level of incompetence yet. Eventually, everyone will end up unqualified for their tasks. Unless they learn how to be ‘creatively incompetent’, that is to pretend that they have peaked.

The tongue-in-cheek idea by teacher and hierarchiologist Laurence J. Peter is more than 50 years old. But I dare say The Peter Principle: Why Things Always Go Wrong hasn’t lost its appeal. If you’d like to know more, check out my long-form essay on the Peter Principle.

2. Chekhov’s Gun

One must never place a loaded rifle on the stage if it isn’t going to go off. It’s wrong to make promises you don’t mean to keep.

A dramatic principle cautioning writers to be aware of the anticipation they’re building for their audience — intentionally or unintentionally. This can happen through props that are placed in a scene or mere plot points. This interesting idea was coined by Russian playwright and writer Anton Chekhov.

While it was intended for use in storytelling, Chekhov’s Gun can easily be applied to our everyday lives. How often do we inadvertently raise expectations that are never fulfilled? For example, if someone promises you a “big surprise”, there better be one in the end.

3. Motivated Reasoning

Can I believe it? Must I believe it?

The idea that we don’t tend to make judgements based on reasoning and evidence. We start with a hunch and go on a quest to have our existing beliefs confirmed. If we find a piece of evidence that does the trick we can stop and present said evidence in case we have to justify why we believe what we believe. Ergo, our reasoning is heavily motivated.

4. Pareto Principle

20% of causes are responsible for 80% of effects.

The Pareto Principle, also known as the 80/20 rule, describes a striking relationship between input and output. It’s a universal law that applies to sports, business and the creative industry. In an organisation, for example, 20% of people do 80% of the work. Or: In 1896 Italy, 20% of the population owned 80% of the land, which was discovered by Italian economist Vilfredo Pareto who gave the principle its name. The Pareto Principle is useful for many things, including making recommendations.

5. The Tenth Man Rule

If nine of us who get the same information arrived at the same conclusion, it’s the duty of the tenth man to disagree. No matter how improbable it may seem.

The tenth man has to start thinking about the assumption that the other nine are wrong.

A form of institutionalised devil’s advocacy. The idea is to avoid groupthink by compelling random members of a committee to make the case against a prevailing opinion. This way, unlikely or unusual scenarios do not fall through the cracks and end up being Black Swans (see below). The Tenth Man Rule was coined in the 2013 zombie movie World War Z.

6. Ship of Theseus

If all the planks of Theseus’ ship are replaced, is it still the king’s ship?

This paradox about identity and identity change goes back to the mythological Greek king, founder of Athens and naval enthusiast Theseus. Either it’s no longer the Ship of Theseus or it is. The thought experiment provokes deeper questions about what constitutes identity and at what point an object, or person for that matter, would cease to be the same.

7. Bikeshedding

The time spent on any item of the agenda will be in inverse proportion to the sum [of money] involved.

Here’s the reason why meetings are a waste of time. According to C. Northcote Parkinson’s Law of Triviality, committees tend to spend the most time on trivial issues everyone can contribute to (such as a low-cost bike shed). The more important, complex and technical projects with far-reaching consequences (such as a multi-million dollar nuclear reactor) are barely discussed and just waved through. Parkinson described this famous example in his 1957 book Parkinson’s Law: Or The Pursuit Of Progress.

8. Dead Cat Manoeuvre

Everyone will shout, ‘Jeez, mate, there’s a dead cat on the table!’ In other words, they will be talking about the dead cat — the thing you want them to talk about — and they will not be talking about the issue that has been causing you so much grief.

Essentially a sneaky tactic to distract someone from an issue in case you’re about to lose an argument. Throwing a (metaphorical) deceased cat on the table will give you at least some room to breathe. The Dead Cat Manoeuvre was popularised by Australian political strategist Lynton Crosby and British politician Boris Johnson. Keep an eye out for any dead cats people throw on your table.

9. Riker’s Razor

If someone’s incompetence is too staggering to be true, they’re most likely faking it and you should find out why.

Enthralling and frustrating as far as interesting ideas go. To be applied to any situation in which someone appears to be willfully inept. This philosophical razor is named after Star Trek Commander Will Riker who is trapped in an enemy’s simulation intended to extract information from him. He cannot believe his crew’s inability to solve simple problems, suggesting they’re “incapable of that level of incompetence”. An idea of my own creation.

10. Betteridge’s Law

Any headline that ends in a question mark can be answered by the word ‘No’.

Like many interesting ideas, the iron rule of headlines cannot be unseen once you’ve learned about it. It’s often used to spark the reader’s interest and curiosity, which can only be satisfied by reading the article to the end. If it weren’t for Betteridge’s Law, which proposes that we’re actually dealing with a non-question. But wait! After only ten concepts, will our list of the Top 25 interesting ideas come to a sudden and unexpected end?

11. Tactical Empathy

It seems like you’re angry.

Empathy of the tactical kind allows you to achieve your negotiation goals without damaging your relationships. By summarising and labelling their emotions, you show your counterparts that you understand where they’re coming from. Seeing the world through their eyes establishes rapport and makes a good deal for both parties more likely. It was coined by former FBI hostage negotiator Chris Voss. He details the concept in Never Split the Difference: Negotiating As If Your Life Depended On It.

12. Fumblerules of Grammar

No sentence fragments. And don’t start a sentence with a conjunction or overuse exclamation marks!!!!!

Proof that rules must always be questioned without exception. Fumblerules are tongue-in-cheek, self-referential types of grammar rules that typically formulate a guideline while breaking it. As such, these kinds of interesting ideas play with language conventions to varying effects. Fumblerules were popularised in 1979 by The New York Times columnist William Safire.

13. SATOR Square


Here to put a smirk on our faces is an ancient word square with five palindromes and semordnilaps that can be read forwards and backwards. The nature of the square stays the same whether the words are read horizontally or vertically. They can even be mirrored. Supposedly, a ROTAS square has magical qualities as it confuses and keeps away the devil. You might have noticed it in Christopher Nolan’s Tenet.

14. Anchoring

I’m about to ruin your day.

A negotiation tactic that exploits the human tendency to make adjustments from our first point of reference. Saying the above to a hotel receptionist would cause him to expect the worst, such as us having flooded our room or even the entire floor. As Chris Voss suggests, if we then confess we’re just another guest asking for an upgrade, they will view our request in a totally different light. This all works because of the Anchoring Effect, a mental shortcut our mind takes when it needs to solve a complex problem fast. It’s another concept of Chris’ bestseller Never Split the Difference.

15. OODA Loop

Observe — Orient — Decide — Act


Natively a military concept, the OODA Loop is a mental model that’s widely used to make better decisions in rapidly evolving situations. In a two-sided conflict, both sides go through the perpetual cycle of observing, orienting, deciding and acting.

The goal is to get inside your counterpart’s OODA Loop by means of speed and/or deception. It was developed in the 1950s by fighter pilot and military strategist John Boyd. But has long been applied to many contexts including business, sports and self-defence.

16. The Linda Problem

Linda is 31 years old, single, outspoken, and very bright. She majored in philosophy. As a student, she was deeply concerned with issues of discrimination and social justice, and also participated in anti-nuclear demonstrations.

Which is more probable?

1. Linda is a bank teller.
2. Linda is a bank teller and is active in the feminist movement.

The Linda Problem, aka the Conjunction Fallacy, suggests that most people choose the second answer because it sounds plausible. However, Linda being a bank teller and active in the feminist movement cannot be more likely than one fact on its own. The probability of the conjunctions can never be higher than the probability of its conjuncts. Psychologists Daniel Kahneman and Amos Tversky came up with this interesting idea in 1981. Similar fallacies are featured in Kahneman’s bestseller Thinking, Fast and Slow.

17. Streetlight Effect

A drunk man is searching for his keys under a streelight. He’s offered help by a police officer who finds out the drunk has actually lost them somewhere else. Asked why he’s looking under the streetlight then, the drunk responds that this is where the light is.

In essence, a common joke used to illustrate a form of observer bias. People often look for information and wisdom where it’s readily available or easy to find rather than in places where the truth might actually be found. In reality, as the saying goes, wisdom is often found where you least want to look. Quite illuminating as far as interesting ideas go.

18. Waiting for Godot

Vladimir: Well? Shall we go?
Estragon: Yes, let’s go.

They do not move.


Needlessly, the two protagonists of Samuel Beckett’s absurd play Waiting for Godot are waiting for a man named Godot without knowing when or if he will arrive. They pass the time with useless nonsense, make decisions to leave but never act on them — until the very end of the play. It has become a metaphor for an event that will almost certainly maybe happen soon. When was the last time you’ve been waiting for Godot?

19. Halo Effect

Alan: intelligent — industrious — impulsive — critical — stubborn — envious

Ben: envious — stubborn — critical — impulsive — industrious — intelligent

The person most people would consider more likable tends to be Alan. Why? Solomon Asch’s example shows that our judgements often depend on what traits we first associate with someone. This is due to the Halo Effect which causes us to judge people by emotions. An initial positive or negative opinion about one characteristic (e.g. eloquence) may lead us to also judge the same person positively or negatively in a different area (e.g. generosity). It’s one of the many eye-opening concepts from Daniel Kahneman’s Thinking, Fast and Slow, which you can also find on my Reading List.

20. Strawmanning

Replacing a potentially strong Proposition A with a similar yet distinctly weaker Proposition B.

Has its name from a feeble dummy made out of straw but comes from the world of rhetoric and debating. The Straw Man Argument is an informal fallacy that gives the illusion of having refuted an argument. An example: –”We should build more playgrounds so kids have more spaces to fool around.” –”So you want that even more kids fall off swings and hurt themselves?” In reality, our counterpart didn’t address what was being said or mischaracterised our position. The reason behind strawmanning is often obvious: Attacking a straw man is easier than taking down a steelman argument.

21. Occam’s Razor

Simpler explanations are more likely to be correct; avoid unnecessary or improbable assumptions.

Essentially a problem-solving heuristic that comes in handy in case you find yourself dealing with multiple competing hypotheses of varying complexity. It’s not always the case, but at least it’s a good starting point for probabilistic thinking.

22. Chewbacca Defense

If Chewbacca lives on Endor, you must acquit! The defense rests.

Renowned legal strategy that intends to confuse the jury with an elaborate argument that makes no sense whatsoever. It features unnecessary repetitions, is full of logical fallacies and is rife with conclusions that are irrelevant to the case at hand. The Chewbacca Defense was concocted by the makers of South Park to make fun of the infamous closing argument of the O.J. Simpson trial. The best way to guard yourself against it is probably to call it out and bring back clarity to the discussion.

23. Planning Fallacy

People tend to underestimate the amount of time they need to complete a task. Even though they know from experience that it will most likely take longer than planned.

Originally a cognitive bias proposed by Kahneman and Tversky. People may fall prey to it due to overconfidence that the best-case scenario will manifest, or merely because of wishful thinking. It’s one of the pitfalls of perfect planning.

24. Tall Poppy Syndrome

If a person grows too tall of a poppy, he or she must be cut down.

Originally going back to ancient Greece and Rome, Tall Poppy Syndrome has become a societal pathology common in Australia. It suggests that anyone who achieves notable success or wealth must be looked upon with suspicion and disparaged. Tall Poppy Syndrome may lead to successful people emphasising their humble beginnings and connection to common folk so as to avoid judgement or cutting.

25. Black Swans

Black Swan events are characterised by their extreme rarity, their severe impact, and the widespread insistence they were obvious in hindsight.

Many have tried, all have failed to predict true Black Swan events such as the rise of the internet. Just like the rare swan species which was deemed non-existent by Europeans. Until it was discovered in Western Australia in 1697.

Black Swans are those unknown unknowns that can only be uncovered when we bend Nassim Nicholas Taleb’s above definition and ignore the hindsight part. Taleb has written in-depth about this concept in The Black Swan: The Impact of the Highly Improbable. According to the former risk analyst, real Black Swans are unpredictable but we can still prepare for them.

Bonus Idea: Hanlon’s Razor

Never attribute to malice that which can be adequately explained by stupidity.

When asking ourselves why somebody did something to us, we should first consider that the person didn’t know what he or she was doing. While it’s possible that we were deliberately hurt, misled or disadvantaged, we first may want to look for the Peter Principle as a more likely explanation.

Closing Thoughts

That’s our Top 25 interesting ideas, concepts, principles and eponymous laws. If you’re keen on more, check out Volume 2 of this list and my tongue-in-cheek essay about AI-generated ideas that defy critical thinking. Also, be sure to subscribe to my free weekly newsletter for 3 Ideas in 2 Minutes.

Honouring Chekhov’s Gun, if you combine the first letters of explanations 6 through 20 (not the quotes), you’ll have figured out the surprise phrase.