I've completed this book and these are my notes in their final form

# The Great Mental Models - General Thinking Concepts

This book discusses common concepts that we can apply to daily situations in the world around us. It builds out and encourages one to attempt to better understand the world around them through these frameworks.

This book was recommended to me by a coworker after a conversation around building out frameworks for solving and approaching problems as well as thinking about things.

# The Map Is Not The Terrain

Core Concept

Maps are necessary distillations of reality.

When you see an explanation of something it has necessary simplifications to share the concept. There is likely far more breadth and depth to issues.

# Concrete Examples

  • Subway Map -> Only shows the subway lines, not all of the underground infrastructure such as pipes, etc
  • Google Maps -> Doesn't show powerlines, etc because its not an issue for drivers

# Where could this be applied?

  • News Stories -> News is necessary distillation of everything happening in the world. If we did record everything that happened we'd need a really good simulation engine 😄
  • Software Engineering -> We have simplified models of how software works that, most of the time, ignores abstractions associated with processors, machine code and memory management.
  • Stories shared -> If someone is to tell you about their trip to the grocery store, they'll probably skip over parts they deem irrelevant, such as locking or unlocking the door to their home.
  • Carpentry -> I don't need to understand why hardwoods behave the way they do, rather a book on carpentry will just describe the properties.

# Circle of Competence

Core Concept

You have things you're good at and things you're not. Be aware of that.

Aside: Its ok to not be an expert at everything or to know everything.

# Concrete Example

The book uses the example of a long time resident of a small town contrasted against a traveler. The long time resident will understand the intricacies of the social dynamics in the town, the impact of the terrain (near a river), etc. A traveler who stays a day may know the map but not understand everything about the terrain.

The dangerous place is where the Traveler acts like an expert on the town and starts selling next the river which easily floods.

# Where could this be applied?

  • What your organization is good at -> If I work for McDonalds and want to start offering low volume, high cost five start dinners I'm likely outside of my circle of competence.
  • Ask for help -> Everyone's going to need help in various places.
  • Impostor Syndrome -> If you feel like an impostor its likely because you do understand

# First Principles Thinking

Core Concept

Get down to the core reasons for why things work the way they do. Do this by Asking 5 Why's or Socratic Questioning

The idea of first principles is to break down concepts or ideas to their core. This is incredibly helpful when working and interacting in complex systems. Since these are core facts or ideas about a discipline, they are the underlying pillars in which a discipline is based on. If you understand those, you can derive the rest.

If you know the first principles of something you can build the rest of your knowledge around them.

If we never take something apart, test our assumptions about it and reconstruct it we end up bound by what other people tell us.

The book provides a number of techniques for actually getting to first principles:

# Socratic Questioning

  1. Clarify your thinking and origins of your ideas. Why do I think this? What exactly do I think?
  2. Challenging assumptions. How do I know this is true? What if I thought the opposite?
  3. Looking for evidence. How can I back this up? What are the sources?
  4. Considering alternate perspectives. What might others think? How do I know I am correct?
  5. Examining consequences and implications. What if I am wrong? What are the consequences if I am?
  6. Questioning with original questions. Why did I think that? Was I correct? What conclusions can I draw from the reasoning process?

# Five Whys

Ask yourself why 5 times to try and land at the core principles. The goal is not to land on something related to how you feel but rather landing on a what or a how.

You can tell that you've hit a principle when the answer to Why is a fact. Landing on a "This is just how it is" answer means that its likely not a principle, rather it is a cultural norm.

# Concrete Example

Robin Warren and Barry Marshall, both Gastroenterologists questioned the long standing medical opinion that there was no bacteria in the stomach after noticing evidence that showed it might exist. This caused them to rethink stomac ulcers and ultimately discover that H. pylori was a cause of stomach ulcers rather than the previously assumed cause: Stress.

# Where could this be applied?

  • Incident Response -> When something is going wrong, try to dig into the root cause of the incident.
  • Corporate Change -> If a reorg is confusing, try to find (or ask your leadership) about the first principles used to decide new organization structure
  • Home Construction -> What is necessary for a home? Why?
  • Developing software -> Is this the best way to do things or just the way we've always done them.
  • Math -> If you understand the underlying proofs, you can derive most formulae. For example, if you understand how the proof for a derivative in Calculus, you can, with some effort, derive the formula for every type of derivative.

# Thought Experiment

Core Concept

Hypothesize, research then think through outcomes that may happen to gain new insights

A thought experiment is a controlled process you go through to understand potential outcomes without ever having to conduct a physical, real world experiment. Certainly it will have drawbacks since the thoughts aren't tested in the real world however this approach can aid in getting towards the correct answer which, most of the time, is all you need.

# Steps

The book outlines a few steps that ensure you're rigorously going through the thought experiment and not just throwing a guess at the wall.

  1. Ask a question
  2. Conduct background research
  3. Construct hypothesis
  4. Test with (thought) experiments
  5. Analyze outcomes and draw conclusions
  6. Compare to hypothesis and adjust accordingly (new question, etc)

# Concrete Example

In a hypthetical game of 1-on-1 basketball where LeBron James and Woody Allen go up against each other, who do you think would win? Why?

Now, think about a hypothetical game between LeBron James and Kevin Durant - Who would win? Why?

Your answers to these are running the thought experiment - Most people have enough context to skip the background research step to understand who the players are then they can simulate the outcome in their mind, using the known information about the players.

# Where could this be applied?

  • Imagining physical impossibilities -> Einstein's famous thought experiment regarding being inside an elevator and being unable to distinguish the difference between acceleration from gravtity or another force such as a cable pulling you.
  • Re-imagining history -> Enables us to ask the question what would have happened if X had occurred in a different manner. For example, what if Franz Ferdinand had not been assassinated? Would we have still had WWI? This is useful for exploring unrealized outcomes but need to be careful because the system of history is endlessly complex. Also, remember when doing research here: The Map is Not the Terrain
  • Intuiting the non-intuitive -> This enables us to think in ways that are not immediately intuitive to us. We can switch up the context of the world, for example in the Veil of Ignorance theory which suggests that when designing a theoretical society, those designing would have to plan as if they were going to be randomly placed across the society to ensure there it is designed as fairly as possible. Another way to apply this: If you were designing HR in your company, what policies would you like in place if you weren't didn't know what your role in the company was or anything about who you are?

# Second Order Thinking

Core Concept

When considering an action, consider not just the results but the effect those results might have as well

Systems are complicated and they permeate our world. It is challenging for us to truly understand systems however when we act as if everything exists in a vaccum, we are far more prone to make mistakes or bad decisions. When developing plans, second order thinking can help us to develop potential consequences of actions that occur.

Note, this concept ties deeply with game theory. If we perform second order thinking, then we can accurately game out approaches - If we act as if a given game is finite, it may not yield the truly optimal outcome.

# Concrete Example

A great example where second order thinking would have helped is the classic story of Cobras in India.

The British Government recognized there were far too many Cobras in India so they instituted a bounty for every dead cobra brought to the Government. What was the reaction of the citizens? They took the simplest approach to profit - They started breeding the cobras. Ultimately the British Government had to stop the bounty program, leaving more cobras in India than when they started.

Another example the book provides is antibiotics in livestock. For years we dumped antibiotics in livestock to keep them safe however over time, that has developed many new bacteria that are antibiotic resistant. If this had been considered early on, it may have been avoidable given it is a second order effect.

A Word of Caution

We need to be careful not to follow the slippery slope argument too seriously here - Slippery slopes generally go so extreme to assume that humans have no rational thought which is far from the truth.

# Where could this be applied?

  • Building Trust -> When considering whether to swindle or build trust, it is worth thinking about the second order effects. If one were to swindle, the swindlee would no longer interact with the person again. If they engage in a trust building deal, then many deals are likely to follow.

  • Leadership -> When making decisions for organizations, thoughts about actions being taken need to consider second order effects. For example, if we re-org this way, how will it impact communication in the organization? How will it impact trust between divisions?

# Probabalistic Thinking

Core Concept

When trying to determine an outcome, attempt to use data available to you to improve your guesses.

The world is endlessly complex and though we'll try hard, we can never predict the future perfectly. Though we can't predict it perfectly, that doesn't mean we can't make informed predictions about what might happen. This principle helps us use our understanding of probability to better inform decisions.

The chapter mentions a few important topics:

# Bayesian Thinking

This type of probabalistic thinking encourages us to understand the context in which things are happening. The book mentions as an example the headline Violent Stabbings are on the Rise. Though this headline sounds scary, it is worth spending time to understand what the relative probability of getting stabbed is. If it increased from .001% to .002%, its unlikely to impact you and shouldn't inform your decision making.

# Fat-tailed curves

We're all used to the bell curve - the curve where everything is perfectly symmetrical and evenly distributed. Though this curve exists in the real world on occasion, fat tailed curves are far more likely as these curves have a much longer tail end to the curve. This means they don't hit zero as quickly and thus there is a decent proportion of the likely events on the extremes of the curve. If we fail to account to understand a situation as having a fat tail, that could cause us to throw out extreme but very real negative (and positive!) outcomes.

# Asymmetries

Asymmetries occur when the probability of our probabilities being correct off. If our guessed probabilities are overly optimistic (which is frequent) we could end up making the wrong decision. It is important to understand this, particularly when folks are trying to sell you on the upside of something. Their estimates might be the high end of the curve rather than the more realistic middle of the road.

# Where could this be applied?

  • Choosing a Financial Advisor -> When considering whether to choose a financial advisor, it is worth understanding what they are promising you. If they promise far exceeded market returns then it is likely an asymmetric probability they're telling you and it is unlikely they'll be able to pull that off. Remember the phrase "These stocks could have an upside of 40%" is very different from the phrase "These stocks will have an upside of 40%" - Your broker will never promise that it will happen, but will say its possible (because it is!).
  • Spycraft -> As a spy, one needs to truly understand the risks they're going into. They need to assess a situation and attempt to understand how risky it may be to decide whether to engage in it. If they are far off they either never get their job done or end up not making it out of the field alive.

# Inversion

Core Concept

Flip the problem on its head and try to think through why something isn't the case or what would need to happen for it not to be true.

Inversion is a simple yet elegant way to ensure you're understaning a problem. There are two main approaches the book mentions which enable you to flip a problem on its head to think it through.

  1. Start by assuming that what you're trying to prove is either true or false, then show what else would have to be true
  2. Instead of aiming directly for your goal, think deeply about what you want to avoid then see what options are left over.

# Concrete Example

The book gives an example of cigarette sales in the early 1900's. The companies wanted to begin selling more cigarettes to women however at the time it was seen as uncool and for men only. Instead of buying ads and trying to sell directly to women, the companies thought through what other things might need to be true to encourage women to buy them - They landed on using marketing through celebrities, TV, etc to convince them that buying cigarettes is cool for women to do. Instead of trying to direct sell them, they thought about how to change the underlying fabric of the sales situation.

# Where could this be applied?

  • Building Startups -> Try to understand the problem space you're going into before you build something. Ask yourself why is this a problem and try to explain to yourself why your solution won't work - In explaining why it won't work, you'll likely come up with a list of issues to ensure you solve as you build the product.

# Occam's Razor

Core Concept

A plurality is not to be posited without necessity - An unlikely case shouldn't be assumed unless we know it has happened

William Ockham was a medieval monk who spent a lot of time thining about the way things are. He landed on this adage which can help us to ensure that we don't jump to dangerous conclusions that impact our lives. It is important that when presented with something unexpected, we don't try to create a false cacophony of potential causes for that thing. Instead we should take a step back and ask ourselves "What is the most likely thing to have happened" and then assume that until we receive data otherwise.

# Concrete Example

The book mentions a number of great examples but since this is a pretty straightforward concept I'll keep it short.

If someone is arriving home late from work what is most likely? That they died in a fiery crash or that they got stuck on something and left the office a few minutes late? Hopefully you said the latter and if that is the case, its also what you should assume to be the case when you're presented with something.

# Where could this be applied?

  • Medical Scares -> Assuming the worst and going on WebMD isn't fun because it seems like every road leads to cancer there. If you've got some medical concerns, by all means talk to your doctor and push them but don't get incredibly worked up about it until you've got data that confirms it, particularly when theres nothing you can do.

# Hanlon's Razor

Core Concept

Don't attribute to malice that which can more easily be explained by stupidity

Not a lot to say here - Don't jump to a conclusion that someone is out to get you or do bad acts, particularly if it is likely that they weren't aware this could be a potential negative outcome.

# Concrete Example

During the cold war, there was a missile officer aboard a submarine who, while underwater, started hearing explosions going off above them. Many crew on the sub thought that war had broken out and that they should surface and fire their nuclear missile however one of the officers thought it was unlikely and understood the risk of making a wrong decision - That single individual altered the outcome of the cold war, all because they followed occam's razor

# Where could this be applied?

  • Job Applications -> I've seen many job applications over my career and unfortunately seen many incredibly qualified people not get a job or even an interview because they applied at the end of the interview cycle and a candidate had already been chosen. When you're applying for jobs its important to know that there are 100's of factors at play that could impact you getting a job and it isn't worth taking it personally when you don't get one because it may not be your fault at all.
  • Relationships -> Assuming stupidity or at least unawareness is usually the best explanation when it feels like someone wronged you in a relationship - Hopefully most of the time, people do not intend to cause harm in any way and so when it does happen it is worth engaging with them to try to understand them and educate them on the outcome. If it continues to happen then it might be time to re-evaluate.