Girish Joshi

The Great Mental Models: General Thinking Concepts

9 min read


“Between stimulus and response, there is a space. In that space is our power to choose our response. In our response lies our growth and our freedom.” ― Viktor E. Frankl

(This quotation is instinctively attributed to the famous Viktor Frankl of Man’s Search for Meaning, however on further inspection, one realises that the actual author of this quotation is unknown. However, this quotation aptly describes the spirit of this book.)

This is Volume 1 of The Great Mental Models series by Farnam Street. Farnam Street is a blog by Shane Parrish primarily featuring writing on mental models, decision-making, learning, reading, and the art of living. In one line the blog is described as “helping you master the best of what other people have already figured out”.

A mental model is how we simplify our world to understand it better. It is the reality in abstraction. A good life corresponds to good quality of thinking. And mental models enhance our quality of thinking by helping us in navigating through complexities by making better decisions with high confidence. However, there is not one metal model that fits all situations, like there is never one outfit for all occasions. It’s like having a set of lenses to see the world around us from a different perspective. And when we learn to see the world as it is, and not as how we want it to be, something begins to change, and then slowly, almost creepily, everything changes.

This book series is going to help you build a latticework of mental models. Below is a summary of all the mental models described in this volume.

The Map is Not the Territory

If I hand you a map, you may soon start believing that the map is more real than the thing it is depicting, forgetting that the map is a scaled-down version of reality.

“The map appears to us more real than the land.” — D.H. Lawrence.

To all those who believe in astrology; without commenting on the authenticity of the claims we can say that those who choose to believe it often forget that it is only a map and not the territory. And therefore, to the believers, it might appear to be more real than reality.

The map of reality is not reality. Even the best maps are imperfect. They are supposed to be imperfect. The perfect map of territory would be just as big as the territory itself, rendering the map functionless. We are bound to forget that there exists a territory separately from the map. This territory contains details the map doesn’t describe. If our aim becomes simplification rather than understanding, then we start to make bad decisions. We can use maps to guide us, but we must not let them prevent us from discovering new territory or updating our existing maps.

Let the maps guide you, but don’t get guided by the map.

“Remember that all models are wrong; the practical question is how wrong do they have to be to not be useful.” — George Box.

Circle of Competence

There are things that you are good at. There are things that you are not good at. And then there is the wisdom of recognising the difference. It’s like Serenity Prayer but with a twist. Instead of “God grant me the serenity to accept the things I cannot change, courage to change the things I can, and wisdom to know the difference.”, it goes like “God grant me the serenity to accept the that there are things I’m not competent of doing, courage to do the things I’m competent of doing, and wisdom to know the difference.”.

We all have a circle of competence, it’s important to know the boundaries of that circle, and to stay inside it while operating. If you don’t have at least a few years and a few failures under your belt, you cannot consider yourself competent in a circle.

“A little learning is a dangerous thing;

Drink deep, or taste not the Pierian spring;

There shallow draughts intoxicate the brain,

And drinking largely sobers us again.”

Key practices for building a circle of competence: curiosity, desire to learn, monitoring, and feedback.

First Principle Thinking

I think of Elon Musk or Richard Feynman when I think of First Principle Thinking.

“The first principle is that you must not fool yourself and you are the easiest person to fool.” ― Richard P. Feynman

It is a fact that if you can’t explain it simply, then you don’t understand it well enough. And that’s where this mental model comes in. Partly the reason why I do this exercise of writing after finishing the book is to ensure that I’m not sleeping or fooling myself.

Knowledge should be built upon the foundational principles. If we don’t learn to take something apart, test our assumptions about it, and reconstruct it, we end up bound by what other people tell us—trapped in the way things have always been done.

Socratic Questioning

  1. Why do I think this? What exactly do I think? (explain the origin of your ideas)
  2. How do I know this is true? What if I thought the opposite? (challenge assumptions)
  3. How can I back this up? What are the sources? (look for evidence)
  4. What might others think? How do I know I am correct? (alternative perspectives)
  5. What if I am wrong? What are the consequences if I am? (consequences and implications)
  6. Why did I think that? Was I correct? What conclusions can I draw from the reasoning process? (questioning the original question)

Thought Experiment

Its analogues to running in a simulation in your head. Take the example of the trolley problem — the classic. A trolley is running on a track which splits in two, on one end (not used regularly) there is one kid, and on the other, there are five. Which end do you turn to? Do you kill the one and save the five? You obviously wouldn’t want to do this experiment in real life, that’s where thought experiments come into the picture. You can run the trolley on the tracks as many times as you want, you can kill children in your thoughts as many times as you want until you come up with a response with a reason. Would you say that five lives mean more than one, even if the one life that was taken was unjust since the kid was playing on a track that was not used, knowing very well the consequences of being on the other track?

Second Order Thinking

Every action has a reaction, we all know, but every reaction has its own reaction. When you throw a pebble in a pond there is never just one ripple. When we make decisions, we forget to think about the indirect repercussions of that decision. If you make abortion illegal, do you know that you’d end up raising the crime rates of the state in a couple of decades? There are always effects of effects.

“When we try to pick out anything by itself, we find it hitched to everything else in the Universe.” — John Muir

You may be focused in one direction, not recognising that the consequences are rippling out all around you. Include second and subsequent effects, if you want to understand the world.

“Once a few people decide to stand on their tip-toes, everyone has to stand on their tip-toes. No one can see any better, but they’re all worse off.” — Warren Buffett

A little time spent thinking ahead can save us massive amounts of time later.

Probabilistic Thinking

They say control the controllable. But when you go out living your life like the bloke you are, you realize that so much in life is uncontrollable, uncertain, and risky. Then how do you live such a life? Probability. Probability is why you don’t think twice before sitting in an aircraft or driving a car. It’s also why you take a lot of your big decisions in life, a lot of times you don’t even know how amazing our brains have evolved themselves to do probability calculations. It’s our only tool to map the unknown and uncontrollable. Yes, there are some pseudo maps available too, but they work on the placebo effect.

The more extreme events that are possible, the higher the probability that one of them will occur. Crazy things are definitely going to happen, and we have no way of identifying when.

Think in terms of probability/chances, and keep updating those probabilities as needed information keeps flowing in.


When you cannot solve the problems moving forward, try solving them by moving backwards. If you cannot decide what you want to do, you can start by deciding what you don’t want to do.

“The test of a first-rate intelligence is the ability to hold two opposing ideas in mind at the same time and still remain the ability to function. One should, for example, be able to see that things are hopeless yet be determined to make them otherwise.” — F. Scott Fitzgerald

Avoiding stupidity is easier than seeking brilliance.

Simply invert, always invert, when you are stuck. If you take the results of your inversion seriously, you might make a great deal of progress in solving your problems.

Occum’s Razor

Simpler explanations are more likely to be true than complicated ones. You can more confidently base your decisions on the explanations that have the fewest moving parts. Complexity serves us more when it comes to creating art than when it comes to real life.

It’s not an iron law but a tendency and a mind-frame you can choose to use: If all else is equal, that is if two competing models both have equal explanatory power, it’s more likely that the simple solution suffices.

“When you hear hoofbeats, think horses, not zebra.”

It states that the probability of simplicity is higher than complexity. The scenario with fewer moving parts is more likely to happen than the scenario with more moving parts.

Hanlon’s Razor

It’s not personal, it’s just stupidity (business).

Never attribute to malice that which is more easily explained by stupidity. The universe is not conspiring against you, what you may think of as malice may just be sheer stupidity, laziness, or inattentiveness. It will help you avoid paranoia or ideology. It is a reminder that people do make mistakes, and it demands that we ask if there is another reasonable explanation for the events that have occurred. The explanation with the least amount of intent is likely to be right.

When we see something we don’t like happen and which seems wrong, we assume it’s intentional. But it’s more likely that it’s completely unintentional. Most people doing wrong are not bad people trying to be malicious. Failing to prioritize stupidity over malice causes things like paranoia.

“I need to listen well so that I hear what is not said.” — Thuli Madonsela

I’m currently reading Volume 2 of The Great Mental Models, the review of that book would follow up shortly.

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