The Great Mental Models, Volume 2: Physics, Chemistry, and Biology

The Great Mental Models #2

by Shane Parrish

From the New York Times bestselling author of Clear Thinking and Farnam Street founder, Shane Parrish.

The second book in the timeless Great Mental Models series.

Time and time again, great thinkers such as Charlie Munger and Warren Buffett have credited their success to mental models–representations of how something works that can scale onto other fields.

Mastering a small number of mental models enables you to rapidly grasp new information, identify patterns others miss, and avoid the common mistakes that hold people back.

Volume 2 of The Great Mental Models series provides a collection of over twenty important concepts from physics, chemistry, and biology in a clear and accessible style. Not only will you better understand the hidden forces that influence the world around you, you’ll also learn how those forces can work to your advantage.

Some of the mental models covered in this book

Leverage: When the application of a small force to one end results in a larger force at the other end.Inertia: An object (or organization) at rest will stay at rest unless acted upon by an external force.Activation Energy: The minimum amount of energy required to incite a chemical reaction.Ecosystems: A community of organisms that have complex relationships to each other.
The Great Mental Models series demystifies once elusive concepts and illuminates rich knowledge that traditional education overlooks. This series is the most comprehensive and accessible guide on using mental models to better understand our world, solve problems, and gain an advantage.

Genres: Science, Psychology, Nonfiction, Self Help, Philosophy, Business, Personal Development

393 pages, Kindle Edition

First published December 1, 2019

About the author

Shane Parrish is the founder, curator and wisdom seeker behind Farnam Street (www.fs.blog).

What started as a personal blog where Shane could explore what others have discovered about decision-making, purposeful living, and how the world works, quickly blossomed into one of the fastest-growing websites in the world.

With over 600,000 subscribers, consistently sold-out workshops, and over 10 million podcast downloads, Farnam Street has become the go-to resource that CEOs, athletes, professional coaches, and entrepreneurs rely on to find a signal in a world of noise.

Shane's work has been featured in nearly every major publication, including the New York Times, The Wall Street Journal, Huffington Post, and The Economist.

Reviews

[Todd Cheng · Rating 4 out of 5]

This book offers an intriguing collection of scientific frameworks applied to social science concepts. For example, the catalyst model from chemistry is used to highlight the importance of learning and its ability to act as a force multiplier. Similarly, the book draws parallels between velocity in physics—defined as speed and size—and Napoleon’s military strategies. Natural selection, typically discussed in the context of biological evolution, is reframed here to explore the adaptation and survival of language.

Each chapter presents a scientific framework and connects it to a metaphor or model that explains a broader, more abstract social issue. This approach creates a unique interplay between the concrete and the conceptual, making the material both accessible and thought-provoking.

The book covers a wide range of topics, including relativity, reciprocity, thermodynamics, inertia, friction and viscosity, velocity, leverage, activation energy, catalysts, alloying, natural selection, adoption and the Red Queen effect, competition, ecosystems, niches, self-preparation, replication, cooperation, hierarchical organization, incentives, and the tendency to minimize energy output. While I might have chosen different analogies or frameworks to link the concepts, the author’s approach remains insightful and engaging.

Overall, this was an excellent read and a strong contribution as part of the two-part series. I also appreciated the additional literary references, which led me to annotate several other books I plan to explore. A thought-provoking and enriching experience for anyone interested in the intersection of science and social dynamics.

[Rishabh Srivastava · Rating 1 out of 5]

This was a frustrating book to read. While the authors brought up some interesting principles/mental models, there was a lot of pseudoscience (like "It is probable that that people first discovered catalysis when alcohol was invented", or "Although the science continues to advance, we lack a comprehensive definition or how many catalysts actually work")

Moreover, they were limited in treating the interesting mental models they did bring up. As an example, Andy Grove and Naval Ravikant treat Leverage as something to build so you can get more output with less input, while the authors bafflingly treat is something that can be used to exploit others.

Having said that, there were some interesting mental models that I meditated on thanks to this book (interesting raisins hidden in a lot of turd)

1. Autocatalysis is when the outputs of a reaction are the same catalysts needed to start it. When this happens the reaction becomes self-sustaining and happens rapidly

2. The Red Queen Effect: You can’t stop adapting, because no one around you is stopping. If you do, your competitive position declines, bringing your survival into question. Every living thing is constantly on the lookout for opportunity, the place to accrue advantage. From Alice’s Adventures in Wonderland: the Red Queen tells Alice, “Now, here, you see, it takes all the running you can do, to keep in the same place.”

3. Gause’s Law: perfect competition between two species requiring the same resources to survive in the same niche is impossible. Two species of bacteria requiring the same resources could not coexist in a petri dish. One species will find its own niche by becoming increasingly specialized to require different resources from the other

On the whole, would not recommend

[Andy One · Rating 5 out of 5]

Do it.read it. Love it.get it.go for it. Be it. See it.believe it.find it.make it.

An obscure review title for a well written, timeless book. My life is changing for the better using models thinking.

[Sven Kirsimäe · Rating 5 out of 5]

I wish I was taught subjects like this at my university. For many of the topics, though, a personal experience might be in need. Thus, I'm humbled to learn them now, and in some cases even be able to associate from personal experience.

[Vitalijus Sostak · Rating 1 out of 5]

This book reads like a strongly simplified selection of some fundamental concepts in physics, chemistry and biology. They're supposed to be practical and applicable in various aspects in life, but it simply does not work for me.
First, it's not a science book, even a very simplified one. There is no system, criteria by which concepts are chosen and their explanation is also inconsistent in structure and details.
Second (and I had exactly same gripes with the first book in the series), the level of "obviousness" is through the roof. Readers that maybe had not attended primary school or do not read at all will find a level of revelation that's exciting, but for the vast majority - nope. Most people, I surmise, know that alloys allow to create new materials with different, useful features than the original components - that's not anything new or even worth reminding. The question is - how do one uses it in a practical way in everyday life? No answer here.

In result, the entire book may be summarized by a dozen or so commandments of mostly trivial quality, like "sometimes the result of using several ingredients is in some way better than any ingredient by itself". But in the end - what to do with that?

Was it a time well spent (reading this book)? For me - rather not.

[Denis Vasilev · Rating 5 out of 5]

Немного неоднозначная книга. Некоторые модели кажутся тривиальными, рассказы слишком отвелеченными. Но иногда попадаются настолько интересные и глубокие идеи, что можно простить и забыть любые недостатки. Хорошое чтение для размышлений в духе Баффета и Мангера

[JD Shaffer · Rating 4 out of 5]

Honestly! I didn't fully read this one. After reading all of the last book, I found that the chapter conclusions were more than enough to give me the core idea. I still think there's way too much fluff in these books. Good idea, but a lot of unnecessary examples and over explanation going on.

[Howard Roark · Rating 5 out of 5]

For what it's worth, this book contains information worth chewing and digesting.

[Debjeet Das · Rating 4 out of 5]

The reason i am giving 4* &not 5* because most of the mental models have been covered in farnam street blog which i had been religiously following since 2018.
This book is good in a sense that it weaves a beautiful structure where that mental tools has been applied in past and where this tools can be followed in day to day sense.
The different stories revolving different mental from battle to discoveries to innovation to philosophy is really fascinating.
I have been reading books on mental tool for a while two more interesting book on mental tool is superthinking which also got lots of mental hacks and thinking fast and slow which talks about heuristics

[Urim Shuku · Rating 4 out of 5]

PHYSICS

1. Relativity

Nothing in life is to be feared, it is only to be understood. Now is the time to understand more, so that we may fear less.

What you see is useful but limited. The less willing you are to accept and acknowledge limitations, the less useful your perspective.

Multiple perspectives are the reality of life.

!-When you see someone doing something that doesn’t make sense to you, ask yourself what the world would have to look like to you for those actions to make sense. Use thought experiment often!

X-We are so used to being on Einstein’s train that we forget it is there. But traveling to new places far outside our normal experiences can jolt us into remembering our train, seeing it in a new light, understanding better its size and shape, and remind us that not everyone is on it.

Perspective often comes from distance or time. If you’re trying to solve a problem and you’re stuck, try shifting your vantage point. Examples of this are moving up and contemplating the bigger picture, moving down and seeing more details, or assuming the perspective of other stakeholders.


2. Reciprocity

Just as someday, if you have something to offer, someone will learn something from you. It’s a beautiful reciprocal arrangement.

!!-It pays to “go positive and go first.” Also, remember that people make mistakes. Assuming there is no maliciousness, it pays to forgive.

Loss Aversion

Organisms that treat threats as more urgent than opportunities have a better chance to survive and reproduce. When it comes to reciprocity, we need to understand, “We are driven more strongly to avoid losses than to achieve gains.

Win-Win Situation

Life is easier and more enjoyable when we act on starting and maintaining win-win relationships with everyone. Reciprocity has been part of our biological makeup for a very long time.

X-If you want an amazing relationship with your partner, be an amazing partner. If you want people to be thoughtful and kind, be thoughtful and kind. If you want people to listen to you, listen to them.

3. Thermodynamics

Entropy reminds us that energy is required to maintain order. You need to anticipate things falling apart and focus on prevention.

The physical world, all of it, only ever has one destination: equilibrium.

!!-Humans put a lot of effort into preventing disorder. If we look at society broadly, we notice that disorder flares up all the time. Examples of this are laws, religions, social norms, customs, and the stories that explain and perpetuate them.

!!-Nothing escapes the laws of thermodynamics. Everything is moving toward equilibrium, including people, culture, ideas, and information. Of course, total equilibrium means no life, so the place where there is no difference in anything is the place where everything rests. Thus, while pursuing difference is worthwhile and necessary, it’s important to understand that any barrier you try to erect will face a relentless pressure to attain equilibrium. Therefore, it’s important to remember that it takes a lot of work to maintain separation.

4. Inertia

For, like a mass in Newton’s first law of motion, once our minds are set in a direction, they tend to continue in that direction unless acted on by some outside force.

Mass matters. It is much easier to apply the force to stop a light object versus a heavy one.

X-Not that there was a particular answer she was trying to prove, but that there was value in scientific process itself.

!!-It’s human nature to allow the current state to remain as changing it requires us to expend energy. Once something is moving in a direction, it’s much easier to keep it in motion. But once something is in motion, it’s hard to stop. The bigger the mass the more effort required.

5. Friction and Viscosity

!!-To overcome resistance, we often default to using more force when simply reducing the friction or viscosity will do. Doing both is more effective than either in isolation. Friction and viscosity can also be wielded as a weapon. Rather than try and catch up to the competition with more effort, you might want to explore slowing them down by adding resistance.

6. Velocity

"If a man does not know to what port he is steering, no wind is favorable to him." - Seneca

!-Velocity challenges us to think about what we can do to put ourselves on the right vector, to find a balance between mass and speed to move in the direction of our goals. Gains come from both improving your tactics and being able to adjust to and respond to new information.

!!-We want to move somewhere so we can look back and identify the territory we’ve covered. This is why having a direction is so important: it lets us evaluate the usefulness of what we are doing by giving us a measurement of where we want to go.

7. Leverage

Levers are everywhere, once you start looking for them.
In human interactions, these levers are not purely physical, but instead items or ideas that have a shared, common value

First, don’t sell yourself short and underestimate the value of your leverage.
Second, keep other people wanting what you have. For leverage to exist, all parties must perceive its value.
Third, understand when you can use your leverage and when you can’t.

Good ideas taken too far often cause unanticipated consequences.

CHEMISTRY

1. Activation Energy

Creating lasting change is harder than creating change. Don’t underestimate the activation energy required to not only break apart existing bonds, but to create new, strong ones. Real change takes effort. Invest more than you think you need to, and you just might get there.

2. Catalysts

Catalysts accelerate reactions that are capable of occurring anyway. They decrease the amount of energy required to cause change, and in the process make possible reactions that might not have occurred otherwise. People and technologies often act as catalysts, increasing the pace of social change and development.

3. Alloying

Alloying is about increasing strength through the combination of elements. One plus one can really equal ten.

Aristotle *discussed five components of knowledge. “They are what we today would call science or scientific knowledge (episteme), art or craft knowledge (techne), prudence or practical knowledge (phronesis), intellect or intuitive apprehension (nous) and wisdom (sophia).

BIOLOGY

1. Evolution Part One: Natural Selection and Extinction

Organisms in nature have survived and thrived for billions of years because they have one powerful trait at their disposal—they are adaptive.

Generalist species are far more resilient than specialists. A rat or a cockroach can survive almost anywhere, a panda less so.

There is a constant interplay between environmental changes and a species’ response to them. If we want to understand why some traits stick around, why some customs carry through many generations, and why some ideas take root and spread through a population, we have to look at their usefulness in their environment.

2. Evolution Part Two:

Adaptation requires leaving or being forced from your comfort zone and into a place where you observe and experience new threats to your security.

!-As in an arms race, where one side invests resources to outdo the other, eventually the cost of the resources is immense, but no advantage is gained. In some scenarios, namely those where there is an end to beneficial adaptation, it is better to look at changing parts of the environment in which you are trying to survive instead of trying to keep up in a race that is undermining your overall ability to adapt. Actions that put the existence of an individual or a species in danger are not the goal of adaptation and not supported by the Red Queen Effect.

Success is measured by persistence.

Adaptations are further constrained by the fact that an organism must be viable at all stages of the adaptation process. What this means on the human life timescale is that if you are compromising your physical health or your sanity, you are not adapting. You are instead weakening your ability to successfully respond to changes in your environment.

"No innovation comes into existence perfectly hewn. Error is thus necessary for the generation of variation."

"Inventions are almost never solitary, isolated creatures; they depend on other inventions that complete them or endow them with new applications that their original inventors never considered."

The stronger we are relative to others, the less willing we generally are to change. We see strength as an immediate advantage that we don’t want to compromise. However, it’s not strength that survives, but adaptability. Strength becomes rigidity. Eventually your competitors will match your strength or find innovative ways to neutralize it. Real success comes from being flexible enough to change, to let go of what worked in the past, and to focus on what you need to thrive in the future.

As Darwin recognized, all life is a struggle for survival.

3. Ecosystem

Everyone has a role, and every role is essential.

!!-The structure of an organization must have the flexibility and adaptability to meet unexpected obstacles, crises, or developments. Go beyond to understand the needs of each employee (even in their personal life) in order to not disturb the ecosystem. The organization is not a closed ecosystem.

Too much of any one external factor can effectively kill a system.

Nothing exists in isolation. Everything is connected. The ecosystem lens reveals that the actions of any one species have consequences for many others in the same environment. Many systems can take care of themselves, possessing abilities to correct and compensate for changes and external pressures.

4. Niches

It’s a lot easier to be empathetic if we look at the environment that shaped someone instead of merely considering the end result. To a certain extent, we are all more predictable than we would like to admit.

5. Self Preservation

"If I gave in to fear, I would end up killing my soul to save my body."

6. Replication

The same happened to the Habsburgs. Without genetic diversity, recessive mutations that would
have otherwise failed to show up in children were reinforced and compounded over generations.

We need to inject newness, or the lack of variation proves destructive.

!!-Rigid specialization—by a genetic code, for example—is not feasible, simply because the code would be excessively large, prone to breakdown, and inadequate for anticipating the many challenges and opportunities an economic entity is likely to encounter during its lifetime. The environment always changes, which is why successful replication has a bit of flexibility built in.

Often a good starting point is what others are doing. Once you get a sense and a feel for the environment you can adapt to better suit your own needs.

7. Cooperation

We often talk of the competition—what they are doing, what direction they are headed—so we can keep up where we need to and not get blindsided or lose too much market share. But how many of us devote resources to looking for “the cooperation”—companies or industries with whom we can partner for mutual benefit?

The more encompassing a shared belief gets, the more we forget it is a human construct.

Cooperation teaches us to seek out and frame interactions based on not only what we can get, but also what we can give. If there was any one model that explains humanity, then this is it.

8. Hierarchical Organization

!!-Hierarchies are inherently and inevitably unequal and unfair. The key is to be aware of hierarchies and work with, not against them. We want to use hierarchies as a tool, not be used by them.

!!-Good leadership is about acting in the interests of the group. The easiest way to lead, is to serve.

!!-Hierarchy is a core instinct. We all look for leaders, even if we are looking at ourselves.

9. Incentives

An incentive is a bullet, a key: an often-tiny object with astonishing power to change a situation.

A good leader “leads his men into battle like a man climbing to a height and kicking away the ladder.” 1 When you can’t go back, your motivation is to go forward together.

It always pays to consider the real incentives that are influencing our choices. We often tell ourselves that our motivation is based in goodness, or doing the right thing, when actually we are incentivized by the allure of rewards.

10. Tendency to Minimize Energy Output

“A general ‘law of least effort’ applies to cognitive as well as physical exertion.

X-Psychologists have a word for the efficiency mechanism in how we think: heuristics. When we’re thinking of making a decision, large or small, we use shortcuts developed from our long experience in the world; in chess terms, we do not consider 10 million different moves, but instead rapidly choose the two or three that are most likely to work.

Experience doesn’t become learning without reflection, and reflection is an energy expenditure.

[Mike Scull]

Not really what I expected at all, but very nicely done. Good wisdom - hopefully I remember some when I need it!

[Matt Chequers · Rating 4 out of 5]

3.5

[Daniel Ottenwalder · Rating 4 out of 5]

The Great Mental Models v2: Physics, Chemistry, and Biology

⸻

Physics

Relativity
• A theory based on empathy — seeing things from someone else’s perspective
• Perspective changes your view of reality
• E = MC²
• Energy = mass × speed of light squared
• Fixed at any frame of reference moving at a constant velocity
• Therefore not fixed reference to measure the physical laws
• Consider your perspective — determine how others see you

Reciprocity
• Why win-win relationships are the way to go
• Why waiters leave a small candy — we give what we get

Newton’s Third Law
• For every force exerted by object A on B, there is an opposite force exerted
• This is how rockets work — they push down on the earth, pushing up the rocket
• We see physics in social situations through quid pro quo
• Most common quantifiable for human dynamics

⸻

Thermodynamics (4 Laws)
• Energy cannot be created or destroyed, only transferred or changed from one form to another (heat or work)
• Entropy always increases in isolated systems — net flow between objects
• As temperatures approach near zero, entropy approaches a constant value
• Zeroth law: if two objects are in thermal equilibrium with a third object, then those two are in thermal equilibrium
• Think about putting hot and cold water together — they reach equilibrium
• It’s a transfer of energy
• This can also be seen in social studies of walls in society that fail to prevent invasion because people are moving towards each other
• They act as a thermos for hot but are inefficient
• Entropy can’t be reversed

Inertia
• Resistance to change
• An object at rest stays at rest and objects stay in motion unless something acts on them
• This applies to social science as well
• Consumption is more about habits, not new thinking

⸻

Friction and Viscosity
• Friction is a force that must be overcome to achieve an outcome
• All objects experience friction
• It’s a matter of how much is experienced and how much energy must be expended to move the object
• Two types of friction:
• Kinetic — when you push something
• Static — when nothing moves, what prevents the move
• Viscosity is how hard one layer of fluid slides over another
• More visual at smaller scale vs friction
• Think plankton moving in the sea vs a whale
• Viscosity can be seen in information sharing in organizations
• Like what happened with Chernobyl in Russia
• Friction can be seen in how Toyota innovated
• Ford & GM focused on capital improvement
• Toyota reduced waste & increased efficiency by reducing friction for frontline workers
• Eliminate and improve processes
• Sometimes reducing friction is easier than exerting more energy

⸻

Velocity
• Speed is just movement; velocity has direction
• Velocity is change in distance over change in time
• Napoleon’s campaign was predicated on velocity
• Unprecedented rate to conquer Europe
• Profound study of history and geography
• Having people buy into your vision by making the victory feel like their behavior contributed greatly
• Simple and clear instruction is key to execution
• His invasion of Russia failed because velocity of a large object is hard to course correct
• Resources were spread too thin

⸻

Leverage
• Output can be significantly greater than input
• Processes in companies create leverage by being able to replace people

Three Types of Levers
1. Force / fulcrum / weight — crowbar opening a door
2. Fulcrum / weight / force — wheelbarrow
3. Fulcrum / force / weight — baseball bat

• For leverage to work you need to know:
1. How do I know when I have it?
2. Where and when should I apply it?
3. How do I keep it?
• Leadership requires followers — without labor there is no leverage
• Don’t sell yourself short — know your value (leverage) to others
• Keep record of what you have (e.g. leverage is past value created)
• Coal towns in West Virginia controlled everything given
• They had a local monopoly
• Only way to fight back was to walk away — you always have some leverage

⸻

Chemistry

Activation Energy
• The energy that must be delivered to start a chemical system
• The reaction breaks bonds so that new ones can form
• Think heating eggs to cooked product / boiling water
• Higher temps = higher activation rates (molecules move faster)
• Changing a habit requires a new loop to replace the old trigger
• Revolutions fail because what it takes to fight is different from what it takes to govern
• In the absence of anything to replace old systems, new problems arise
• Japan, South Korea, and Taiwan changed their systems to maximize output from agriculture
• Then focused on enabling entrepreneurs in manufacturing and financial policies to support efforts
• Low ROI in short term for higher ROI in future
• Philippines, Thailand, Indonesia did not reform land for maximizing farming
• Manufacturing was insular, servicing local markets vs export
• Financial policy maximized short-term ROI, then suffered in times of distress
• Need to know how much activation energy is needed to make change
• Charging bonds

⸻

Catalyst
• Catalysts accelerate change
• Many types of catalysts, different reactions, lower activation energy
• Catalysts can sometimes be reused
• Creation of alcohol uses yeast as a catalyst for fermentation
• Reaction already wants to happen, catalyst speeds it up
• Printing press acted as catalyst for knowledge transfer
• Reduced cost and increased access
• Black plague was a catalyst for social change
• Less people → higher wages
• Need to improve yield → tech innovation
• More science to understand cause

⸻

Alloying
• Alloying is making the sum greater than its parts
• Combining two or more metals / non-metals
• Bronze = 90% copper + 10% tin
• Steel = iron + carbon
• Applies to building teams
• Knowledge is an alloy formed from theory and experience

⸻

Biology

Evolution — Part One: Natural Selection and Extinction
• Environmental pressures shape groups, spurring to evolve or die
• Natural selection: more favorable a trait is for a specific environment, the higher chance of surviving long enough to reproduce
• Extinction has many causes; one cause is competition
• With a better adapted rival
• Another common cause is environmental change
• Climate change, deforestation, volcanoes
• Extinctions don’t typically happen in isolation
• They take out other species in ecosystem
• Wear and tear from optimizing for one environment makes species less able to change
• Generalist species have greater adaptability than specialists
• Rats & cockroaches vs pandas

⸻

Evolution — Part Two: Adaptation Rate & Red Queen Effect
• We have to deal with the environment we’re in, not the one we wish we were in
• Thrive only as well as they have to, rather than optimize
• Populations are successful relative to specific environment and competition
• Dispersancy penetrates and conquers from weaker positions
• Technology available with tanks piercing the Maginot Line
• Red Queen effect
• Least fit species die first
• You can’t stop adapting because no one around you is stopping
• Evolution is ongoing
• Exaptation
• Using what you already have
• Feathers originally for warmth, later for flight
• Bubble wrap invented as wallpaper
• IBM used punch cards for shipment protection
• Complacency will kill you
• The stronger we are, the more fragile
• Let go of how environments worked to move forward

⸻

Competition
• We live in a finite world of resources
• All life is a struggle for survival — zero-sum game
• Competition creates innovation

⸻

Ecosystems
• Community of interacting species and non-living environment
• Components play a part in determining characteristics
• Humans tend toward intervention bias
• Sometimes ecosystem needs fire
• Clearing part of forest allows sunlight for others
• Harder we fight to control ecosystems, the harder they fight back
• Preserving ecosystems more crucial than preserving near-extinct species
• Ecosystems are not static — constantly changing
• Some robust, others fragile
• Resilience is how fast ecosystem recovers
• Law of minimum
• Yield dictated by lowest essential nutrient

⸻

Niches
• Generalists can survive in almost any setting
• Specialists thrive in narrow ecosystems but face extinction if environment changes
• Generalists face more daily competition and stress
• Specialists have less daily stress but higher extinction risk
• Competitive exclusion principle
• Two species competing for same niche cannot coexist
• Convergence happens in nature
• Same effective forms appear repeatedly
• Birds, dinosaurs, bats

⸻

Dunbar’s Number
• Humans can maintain ~150 relationships
• Capacity tiers:
• 5 people — inner core
• 15 — close friends
• 50 — friends
• 150 — community with trust
• 500 — acquaintances
• 1,500 — faces you recognize

⸻

Self-Preservation
• Pain = bad; survival instincts protect us
• No universal definition of a great life
• Reflexes = automatic involuntary actions
• Territorial behavior linked to resource protection
• Sometimes we sacrifice ourselves for group or future children
• Fight or flight is complex interaction
• Rewards through authority are an effect of self-preservation

⸻

Replication
• DNA makes copies through cell division
• Three requirements:
1. Code representing what to replicate
2. Means of copying
3. Place to process code and construct replica
• Replication uses recombination — components combined in new ways
• Sexual reproduction → diversity → improved fitness
• Inbreeding shows closed systems
• Sweet spot of replication
• Rigid enough to copy
• Flexible enough to adapt
• German army lost because unable to adapt to environment
• Commander’s intent:
• Formulate
• Communicate
• Interpret
• Implement
• Commanders must explain rationale
• Establish limits
• Get feedback
• Recognize individual differences
• Cultural items replicate
• Tea adapted across China, Japan, Persia

⸻

Cooperation
• Symbiosis — organisms cannot perform all functions alone
• Cooperation needed for adaptability
• Bacteria in squid producing camouflage
• Squid provides stable environment
• Shared beliefs enable human cooperation
• Money, religion, corporations
• Humans are more than sum of parts

⸻

Hierarchical Organization
• Common in nature
• Linear dominance ranking reduces fighting
• Implied contract:
• Leaders provide food direction
• Protection
• Reinforce order
• Hierarchies persist despite costs
• Be aware how they work and use as tool
• French Revolution ended in hierarchy
• Leader must be best suited, not just first

⸻

Incentives
• All animals move toward reward, away from punishment
• Evaluated through self-esteem and narrative
• Behavior responds to internal & external factors
• Skinner box
• Infrequent reward creates stronger behavior
• Anticipation is the reward, not the action
• Thalidomide example
• Money and incentives overrode safety
• Cognitive dissonance prevents change

⸻

Tendency to Minimize Energy Output
• Conserving energy seen in all animals
• Brain uses heuristics to reduce cognitive load
• Satisficing — accepting minimum acceptable outcome
• Heuristics work in consistent environments with unambiguous feedback
• Firefighters operate well (physics & chemistry)
• Stock market harder
• Biases:
• Anchoring
• Availability
• Representativeness
• Affect heuristic (replace hard question with easy one)
• Counter by engaging level-2 thinking
• Remember base rates
• Pay attention to information quality

[Siddharth Gupta · Rating 4 out of 5]

Much of this book's appeal lies in the fact that a book on this topic ought to exist, and there was none before this came along. Anyone with a better than average understanding of the natural sciences - stuff that is taught in high school - would have an intuitive feel for these concepts. It is therefore, great that those concepts have been modelled by the author for use beyond their original discipline.

I would have happily given the book the full monty if it delved deeper. Many models were backed up by anecdotal evidence. This surely makes the book readable but a lack of epistemological slant makes the book less practical, in my humble opinion. A modicum of hard evidence to back up the application of the model to any setting/industry/era, should elevate the work to a whole new level. I hope that to this end, at-least the book achieves mass readership which it so deserves. Eagerly looking forward to the third volume in the series.

[James Browning · Rating 5 out of 5]

this series has been exceptional for creating a way of categorizing problems both in a personal and professional context.

[Corban Till · Rating 5 out of 5]

Absolutely Amazing.

[David Parkinson · Rating 4 out of 5]

A book for nerdy people such as myself. Basically just tons of analogies between science & life! Some more literal than others. Interesting stories!

[Derek · Rating 5 out of 5]

A refreshing set of unique examples and stories. I was pleasantly surprised.

[Lloyd Downey · Rating 1 out of 5]

I’m a bit mystified by this book. (Admittedly, I’ve only read it as the Blinkist summary version so I would have missed a lot of the nuances).....I though that I would be getting a great set of mental models that I could apply to life or work, or politics etc. Instead, I’m left with the feeling that there are a few old ideas there that have been re-worked and the author is claiming them as great insights. For example: Evolution:.....Yes, I know early adaptors (and first to market) have advantages.....and it was a great idea by Charles Darwin ....with many others hitting their heads and asking “Why didn’t I think of that?”......But a great mental model? Well maybe.....certainly better than most of the other examples.
Then the ideas about catalysts and alloys.....Ok if you want to apply these scientific facts to other situations. But was the printing press a catalyst or simply a technological breakthrough....like the internal combustion engine?
I guess thinking of combining knowledge from different fields is a bit like making an alloy....but you could also compare it to mixing a cake. Is the analogy helpful. Well maybe but not very helpful. And what was the point of Bethune’s story.... the guy died an unsung hero. Yep. I guess there are millions of them. Is the point to do your best or volunteering is a good thing in itself? But where is the mental model here? I just don’t get it. Same with the stories about France in 1788. Where is the mental model here (other than a hierarchy...which, I take, he thinks is bad). ....Here’s a few extracts from the book.
“In the early twentieth century, newspapers began running sensational stories about absinthe’s effects. “It’s as addictive as opium! It drives drinkers insane!”....Meanwhile, not much was being written about lead,
The claims about absinthe were bunk. It wasn’t any more harmful than other high-percentage alcohols.......Lead was different. The evidence against it wasn’t overstated–it was simply ignored. The Roman architect Vitruvius had warned his contemporaries against putting water in lead pipes around 15 BCE..........Lead continued to be added to paints and gasoline well into the 1980s.
Substances like lead and absinthe have a kind of “societal mass,” and the same rule applies. Lead had been used for millennia and “stopping it”–that is, getting rid of it–meant changing everything from how walls were painted to how cars were fuelled......Absinthe, by comparison, was a lightweight: it hadn’t been around long and all it did was get people drunk.
Slow zebras get eaten. What this striped equine needs, then, is speed.
Over time, the zebra population as a whole gets faster as this useful trait.....Natural selection doesn’t just explain the speed of zebras–it can also help us understand the history of cultural “organisms” like languages.....In the natural world, plant and animal species can go extinct while leaving descendent species behind that survive. Which is precisely what happened to Latin. In the post-Roman world, societies turned to the offshoots of Latin–Romance languages like Portuguese, Spanish, and Italian.......They were much easier to learn and, as a result, much more useful. [ But Spanish also included/absorbed the Mozarabic languages and the languages of the Alans, and Vandals and Visigoths etc. ]
Early adaptors come out on top.
During the Industrial Revolution, light peppered moths were quickly picked off. That left much rarer black peppered moths, which were suited to this new landscape. They survived in greater numbers.
France constructed the Maginot Line....On paper, the country was more than ready to meet the German threat.......But in 1940, Germany bypassed the Maginot Line and launched a devastating offensive......French strategists assumed the next war would be much like the last war and planned accordingly.......General Guderian, a German tactician
organized independent tank divisions capable of deep and swift strategic penetration. It was an adaptive change
Catalysts accelerate chemical and social change.
Europe was a different place after the Black Death. Fewer people meant there was more land than could be worked. This resulted in lower rent.....It was also harder to replace workers, which boosted wages.
In chemistry, a catalyst is a substance that accelerates change. It doesn't make anything happen that wouldn't happen otherwise, but it does reduce the amount of time it takes for reactions or changes to occur.....Catalysts aren't always chemical in nature. Take the printing press, which accelerated a social "reaction".
Knowledge is an alloy just like bronze or steel.
Leonardo da Vinci's thirst for knowledge was boundless. He wanted to know everything.
Why did Leonardo need all this know-how? Well, he understood that combining different sources of knowledge adds up to something greater than the sum of its parts.
The ancient Sumerians started producing bronze around 5,000 years ago... Bronze, compared with copper, was much more durable. It was a great material if you wanted to make weapons and tools........Then there's steel, an alloy of iron and carbon.....Knowledge can also be thought of as an alloy.....To operate a car, you need to know the rules of the road. Aristotle calls this episteme-theoretical knowledge. It's also important to understand what various pedals and buttons do. That's techne, or "craft knowledge."
you also have to anticipate what other drivers are going to do, which requires nous-intuitive apprehension.......If you ease off the gas pedal.....when the light is green, you're using phronesis-prudence born of experience.
You get what you give – in physics as in life.
During World War I, Bethune served on Europe's battlefields as an ambulance guy. ....In 1936, he volunteered as a trauma surgeon with the Republican side in the Spanish Civil War......Bethune's selflessness and heroism brought neither fame nor fortune, however. In fact, he died in 1939, after contracting septicemia. He was just 49 years old.....Good deeds don't always generate equally good outcomes. But reciprocity can still help us interpret Bethune's life story.....Volunteering is strongly predictive of better mental and physical health, life satisfaction, self-esteem, and happiness. Selflessness, in other words, may well be its own reward for people like Norman Bethune, giving them energy, drive, and a sense of purpose.
Humans might not be able to live without hierarchy, but they can choose better leaders.
In rural France, 1788......French society looked a bit like a chicken coop. It, too, has its pecking order.......At the top, there's the king, whose word is law. Below him are the clergy and aristocrats. They owe obedience to the monarch but little else. At the bottom, there's the so-called Third Estate: the mass of rightless, overtaxed peasants and workers.......Top-down systems are bad for those at the bottom of the pile.......Eventually, Napoleon proclaimed himself the emperor of France and created his own hierarchical order.......The problem with bad leaders is pretty simple. The people who put themselves forward for leadership positions are fierce competitors like Napoleon. They're great at winning power but less adept at exercising it.
Final summary
The key message in these blinks: Why are zebras so fast and how come no one speaks Latin as a mother tongue? Why did governments ban absinthe but ignore the dangers of lead exposure? And what do flea-ridden rats have to do with the Renaissance? Surprisingly, the "hard" sciences-physics, biology, and chemistry-can help us answer these questions. That's because these disciplines are built around a set of core concepts that do more than explain nature-they can also help us understand our own world and its history”.
My overall take on the book? Sorry, but I’m not convinced that by taking a few examples from the world of science: like evolution, alloys, catalysts....and a few others (apparently from sociology) like hierarchies, and volunteerism.......that these are a coherent set of useful mental models. I found the narrative disjointed and illogical in many ways. Just doesn’t hang together for me. One star.

[Kilian Markert · Rating 3 out of 5]

Second part of the series on mental models, this one is much longer and in my opinion way too long. The book goes into even more length than part 1 trying to give real life examples connected to the mental models.

Some of them didn't really fit, while a few where quite interesting and others left me asking, so what?

Also a lot of it is just pretty obvious and not containing any valuable lesson for your life.

Valuable take aways however where:

1. Relativity and limited perspective
"You will always have limitations to your frame of reference that you need to account for in an effort to better understand reality. You have a limited perspective.

Many problems become clearer if you extend the timeline. What does this situation look like in the weeks, months, and years ahead?

Assuming different perspectives allows you to gain a more complete understanding of what’s really going on."

2. Loss aversion
people are willing to risk losing $ 100 for every $ 250 of potential gains. The loss aversion coefficient is 1: 2.5.

3. Speed vs velocity

"Velocity is often confused with speed, but the two concepts are very different. Speed is just movement; even if you are running in place, you have speed. Velocity has direction. You must go somewhere in order to have velocity. This model teaches us that it’s much more important to pay attention to where you are going and not how fast you are moving. "


4. Fun fact about goosebumps
"The human goosebump reaction to stress or fear is a vestigial response, based on how our ancestors would have fluffed up their fur to look bigger when confronted with a predator."

5. Reminder about cognitive dissonance

"Humans don’t like cognitive dissonance—“the state of tension that occurs whenever a person holds two cognitions (ideas, attitudes, beliefs, opinions) that are psychologically inconsistent.”

And then justifying things irrationally to avoid that dissonance.

[Tim G · Rating 3 out of 5]

My anchor for this book and review, was from Volume 1 in the series, which I thought to be a resourceful and worthwhile read.
Volume 2: Physics, Chemistry and Biology, and perhaps due to the science based focus, I found to be less engaging. The book was longer, and felt to be a longer duration to consume.
I do have an interest in Science, and while the correlations of the science headings to extract the learnings, this science aspect just didn't seem to resonate and constituted in a less engaging novel.
However, sections do have merit, and after rereading my highlight,s I was reminded of the some good tidbits which are littered throughout. Although, these were less in comparison with the first book in the series.
I was also able to use the book as a reference for one of my uni assignments, so there was an added benefit.
Some of the standout highlights:

'Many, many men have been just as troubled morally and spiritually as you are right now. Happily, some of them kept records of their troubles. You’ll learn from them—if you want to. Just as someday, if you have something to offer, someone will learn something from you. It’s a beautiful reciprocal arrangement.' - J.D Salinger.

'When it comes to reciprocity, we need to understand, “We are driven more strongly to avoid losses than to achieve gains.'

'Eventually your competitors will match your strength or find innovative ways to neutralise it.'

[Adam · Rating 5 out of 5]

Gorgeous book that will help you apply mental models from the sciences.

[Will Morgan · Rating 5 out of 5]

An excellent application of scientific principles to thought patterns. This book is intriguing throughout. I say this being totally unbiased by my appearance in the acknowledgements.

[Ravi Gangwani · Rating 4 out of 5]

Not bad. Some of the models were pretty good.

[Bohdan Shtepan · Rating 2 out of 5]

Even Worse Than the First Book

First and foremost, don’t be misled by the title. This book—and seemingly the series as a whole—is not about mental models in the traditional, cognitive-scientific sense (i.e., fundamental internal representations that help us make sense of the world). Instead, the term is used metaphorically, often closer to “conceptual frameworks” or general metaphors. It would be more accurate to think of these as loosely organized heuristics rather than true mental models.

The series positions itself as an extension of Charlie Munger’s concept of a “latticework of mental models” meant to cultivate worldly wisdom through multidisciplinary thinking. Yet, it utterly fails to deliver on that promise. Munger emphasized the integration of “big ideas” from the “big disciplines”—particularly psychology and philosophy. These disciplines are notably absent in Shane Parrish’s treatment. His work reduces Munger’s profound interdisciplinary vision to a set of disconnected historical anecdotes and textbook-level definitions from the natural sciences.

The structure of the book is simplistic and repetitive: each chapter begins with a basic idea from physics, chemistry, or biology (often lifted verbatim from sources like Wikipedia), followed by two or three vaguely related historical examples or narratives. These “supporting” sections often rely heavily on excerpts from popular books, strung together with minimal original analysis. The overuse of lengthy, sometimes irrelevant quotations makes the reading process feel tedious—almost as if the author has little to add beyond what others have already said.

Worse still, the book contains multiple factual inaccuracies and unsubstantiated claims. A few that stood out, due to my familiarity with the subjects, include:
- Napoleon’s Egyptian and Syrian campaigns took him farther from Paris than his Russian campaign, contrary to the book’s claim.
- The concept of “Vulgar Latin” has long been challenged and is largely obsolete in modern linguistics.
- The economic rise of post-war South Korea, Japan, and Taiwan was heavily influenced by U.S. protectorate status—an important geopolitical context the author overlooks.
- The incorrect usage of “the Ukraine” and Russian transliterations like “Kiev” and “Chernobyl” show a lack of editorial rigor and cultural awareness.
- The discussion of Thomas Sankara lacks crucial nuance. While often celebrated, Sankara was a dictator with a deeply complex legacy that included severe human rights abuses—details the author omits entirely.

These are just a few of many such issues that reflect not only the author’s lack of formal training in the subjects discussed but also poor fact-checking and weak editorial oversight.

Ultimately, this book might appeal to readers looking for a lightweight collection of random facts and anecdotes—assuming they’re not too concerned about accuracy. But if your goal is to genuinely understand or apply mental models, this book is not just unhelpful—it could be actively misleading.

[Richard Thompson · Rating 2 out of 5]

We all think by way of analogies, whether we are conscious of it or not. It's one of the fundamental ways that the human mind works. And when I think about a how to solve a problem or plan for the future in one area of my life, I often think of analogous situations in other areas where I have knowledge or experience in the early ideation stages of problem solving. So I thought that this series of books might be useful for me in helping to be better at something that I do already. It wasn't.

Most of the models discussed here were things that I'd probably think about anyway in an analogous situation, but more than that I often didn't agree with the way that models were applied in the text. Beyond that, Mr. Parrish didn't acknowledge the limitations that are inherent in this approach. Physics and chemistry are fundamentally different from business and financial questions and interpersonal relationships. There are interesting and helpful similarities and using a loose connection to stimulate your thinking can be great. But if you get too literal, if you convince yourself that the analogy is exact, it can lead you badly astray. So this kind of thinking with models is really only useful to get you started and rarely has much value when you get to the execution phase of a plan. Yes, it can still be a touchstone, but in almost any situation where you have to be strategic, you need to also be flexible and understand the human factors involved.

[Evan Micheals · Rating 5 out of 5]

I have listened to Shane Parrish on The Knowledge Project for years. He is obsessed with better thinking and mental models. This is the second of his three book series and it is great. It has all the qualities of The Knowledge Project: Deep; Thoughtful; Concise; Intelligent; Reflective.

This book uses the models within Physics, Chemistry, and Biology to explain the models, and then use these as metaphors to explain them as broader thinking models. Parrish explains the model and how it works in the natural world, suggests what it implies, and then gives an analogous story drawn from history to show both a positive and negative application of the mental model. He succeeds in the Charles Munger idea of developing a number of models as different ways of thinking about problems in life.

I learned more about science and its philosophical application. It is the sort of book I want to return to regularly to cement the knowledge. I remain a fan of Shane Parrish and The Knowledge Project. He is one of the wisest content developers/providers I have come across. I will read the third book when it is released.

[R.C. · Rating 4 out of 5]

A solid indie book about logic and philosophy and psychology, with a focus on avoiding the failures that are all too common with human brains. The author obviously pulled a lot of this from listening to successful businessmen, but the info is solid and will probably feel self-evident to anyone who has looked into self-help or logical fallacies at all: understand what you don't actually know, play to your strengths, identify your blind spots, be open to new information and ideas, etc. It's the sort of common-sense approach that most folks have picked up 90% of, but which the author is right: it's not covered in school and some people may not have picked it up elsewhere.

Also, let's face it: if you've got a problem and read a book like this, it's likely that SOMETHING in there will knock a new idea loose, or give you a new perspective. That was the case with me.

Overall, this isn't the most polished or well-rounded book and it's obviously just one guy's passion project, but he explains what he wants to explain well, and it struck me as the type of book it's good to have around, just for an every now and then brain-cleaner.

[Scott Wozniak · Rating 4 out of 5]

This book takes some of the major scientific ideas of our day and then applies them in metaphorical ways to life and leadership. For example, inertia can be used to understand why it's hard to change habits and the second law of thermodynamics (everything slides to disorder/decay unless acted on by an outside energy source) can be used to show how we need to keep pouring new ideas and tools and people into our organizations to keep them healthy and strong.

It's well written and easy to read, especially good at explaining the science in a way that doesn't require prior technical knowledge. However, the author couldn't resist making disparaging comments about worldviews and cultures that he doesn't agree with, distracting from the flow of the book for me. To be clear, I like thoughtful challenge, but the single sentence added to the end of the paragraph without any explanation or evidence was unhelpful, especially in a book about how scientific thinking was a helpful way to think. Still worth reading, though, as the main points were good food for though.

[Bryan Oliver · Rating 5 out of 5]

The quality of your thinking depends on the models that are in your head.

Just a great read, solid concept, and a true path to synergistic knowledge and abstract reasoning. Having multiple perspectives on the same issues is just the reality of life; combining and learning about various perspectives puts you in a position to make better decisions and live a happier, wealthier, healthier, and more 'true' life instead of half ass guessing your way through every situation you encounter.

When you see someone doing something that doesn’t make sense to you, ask yourself what the world would have to look like to you for those actions to make sense.

The authors examples and analogies across a wide range of spectrums have such a complete and fulfilling framework to them. I'm looking forward to reading the other volumes in this series and would recommend this book to anyone who cares about - not exactly self-help - but just approaching everyday situations with a more complete and accurate viewpoint.