The Great Mental Models, Volume 2: Physics, Chemistry, and Biology (The Great Mental Models Series) - By Shane Parrish & Rhiannon Beaubien
Date read: 2025-07-07How strongly I recommend it: 9/10
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Mental models act as cognitive frameworks to help understand, interpret, and navigate the world around them. Book two of a four volume series showcases concepts found in physics, chemistry, and biology and how they can apply to business and decision-making. A fantastic book on thinking better and for making better decisions.
Contents:
- RELATIVITY
- RECIPROCITY
- THERMODYNAMICS
- INERTIA
- FRICTION AND VISCOSITY
- VELOCITY
- LEVERAGE
- ACTIVATION ENERGY
- CATALYSTS
- ALLOYING
- NATURAL SELECTION AND EXTINCTION
- ADAPTION RATE AND THE RED QUEEN EFFECT
- ECOSYSTEM
- NICHES
- SELF-PRESERVATION
- REPLICATION
- COOPERATION
- HIERARCHIAL ORGANIZATION
- INCENTIVES
- TENDENCY TO MINIMIZE ENERGY OUTPUT
My Notes
We often think someone is wrong because they see things from a different perspective than we do. Relativity helps us to understand that there is more than one way to see everything. That doesn't mean everyone's perspective is equally valid, only that we might not have the most complete view into a problem or situation.
You are always going to have an imperfect perspective. You can't see everything at once. Nor will you be able to completely trust that everything you do see is viewed by others.
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.
When someone gives you something - an opinion, a report, an article, a plan - consider how it is framed. Who is involved in this information, and what do you know about their vantage point? Knowing the factors that influence how a person frames issues helps you understand their perspective and how you can use it to augment your own.
Another way to change your perspective, aside from looking at the situation through the eyes of others, is to 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.
When you act on things, they act on you. For every action there is an equal and opposite reaction.
Life is an iterative and compounding game. In the words of businessman Peter D. Kaufman, it pays to "go positive and go first." Also, remember that people make mistakes. Assuming there is no maliciousness, it pays to forgive.
The more people you help, the more people you will have willing to help you.
The laws of thermodynamics have many metaphorical applications. We can recognize that we will be influenced by the behavior of the people around us; therefore, it's important to be wise in choosing who they are. Entropy reminds us that energy is required to maintain order. You need to anticipate things falling apart and focus on prevention.
Two different states, whether of matter or people, will be impacted by what they are exposed to. An ice cube will undergo a temperature change if left outside in warmer air, and similarly a group of people will undergo changes in custom based on whom they interact with outside their group.
The longer we've been doing something, the more it has become part of both our identity and our understanding of the world. Thus, the amount of effort required to change a habit is greater proportional to the length of time we've had it.
Once we consider a story true, it takes a great deal of force to change it. Data alone is rarely enough. This is part of the reason why the proof of something being harmful is not always enough to produce a change in behavior.
Strong beliefs can stay strong while being flexible. In fact, if we continually refine and develop them based on new information and experiences, they can continue to support us through challenges.
There are two important aspects to using friction and viscosity as a model:
Friction and viscosity can also be wielded as weapons. Rather than try to catch up to the competition with more effort, you might want to explore slowing them down by adding resistance through increased regulation, bureaucracy, or other clever ideas. In the end, reducing resistance is often easier than adding force.
Velocity moves you toward a goal. Speed does not. If you are in a race and you run in a circle, you might move with a lot of speed, but you're not closer to your destination. Progress matters more than activity.
Better to go in the right direction slowly than in the wrong direction with speed.
Leverage is achieving results significantly greater than the force you put in.
The best way to have leverage in any deal is to not need the deal at all.
At its core, leverage is about the amplification of effort. Think of a crowbar prying open a stubborn lid, or a pulley system hoisting a heavy load. In each case, the tool or mechanism allows its user to overt force in a way that multiplies their natural strength and capacity.
Activation energy is needed for everything from getting up in the morning to revolutions. It's the ingredient that starts a reaction, breaking apart the current state of affairs and transforming it into something new.
The key to activation energy is to evaluate how much of it you need to see the reaction through to its conclusion. At what point have you gone far enough that you can't go back?
"Don't let a good crisis go to waste" - Success can act as a catalyst for failure, just as failure can be a catalyst for success.
For many people, unpleasant events, such as getting fired or rejected, prove to be catalysts for tremendous personal growth. For example: COVID was a catalyst for remote work.
Alloying combines components in specific combinations to produce a substance that can achieve something the individual elements cannot.
A team in which everyone has good ideas and nothing else won't be as strong as a team that also includes someone who has an eye for which ideas are worth pursuing and the skills to make them a reality.
Understanding that knowledge is an alloy of experience and theory that can be further strengthened with elements of curiosity, imagination, and sharing gives us the ability to develop it as a true source of power in our lives.
Adapt or die.
Our skills, our knowledge, our ways of thinking must constantly evolve to keep pace with an ever-changing world. Those who consistently adapt are the ones who thrive in the long run.
We don't have to be objectively best, just better than those we are competing against.
On the human timescale, adaptability is about recognizing when the way you have done things in the past is becoming less and less successful in a changing environment. It requires you to innovate, with ideas that will improve your chances of success.
Adaptation isn't a onetime event but a continuous process. It's not about reaching a finish line but about maintaining a lead in an endless race.
The structure of an organization must have the flexibility and adaptability to meet unexpected obstacles, crises, or developments. The stronger and more resilient a system, the more easily it can adapt and bounce back.
External stability is important for overall success. Even if you can't control the external factors, you must pay attention to them. We must also do what we can to influence the external factors that are required to keep our system going.
Success is often a product of environment. Understanding how environments impact performance changes how you hire. Someone who thrives in one environment easily fails in another if part of their performance was the operating environment. This is why hiring a superstar away from a competitor, without understanding the role of environment in performance, often disappoints.
It's a lot easier to be empathetic if we look at the environment that shaped someone instead of merely considering the result. To a certain extent, we are all more predictable than we would like to admit.
By specializing in something unique and valuable, you can create a space where you can excel, where your combination of skills can thrive. The key is to find the niche that fits you, that rewards your strengths and neutralizes your weaknesses.
Successful niche occupants are often those that can adapt, that can evolve their niche as the world around them changes.
Specialists have less competition and stress, but only in times of stability. Generalists face greater day-to-day challenges for resources and survival but have more flexibility to respond when times change.
For humans, survival is not merely a binary, like dead/alive. We don't want to just continue breathing, but to have a life that we perceive as having meaning, value, or at least a point.
When we're too focused on avoiding threats, we can easily miss opportunities right in front of us. Left unchecked, self-preservation can lead to stagnation. The key, then, is to find balance to protect what's essential but also be willing to let go of what no longer serves us.
Commander's Intent:
Replication is useful outside of biology too. As a mental model, it teaches us that we don't always need to reinvent the wheel. When you're just getting started, the quickest way to make great leaps is to imitate what others are already doing. This establishes an average baseline of performance. Once you get a sense and a feel for the environment, you can innovate and adapt to set a new baseline.
If you want to go quickly, go alone. If you want to go far, go together.
The lesson here is to consider how often you look for opportunities for collaboration. We frequently 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?
Hierarchies serve an important function. They enable complete strangers to know how to treat one another without wasting the time and energy needed to become personally acquainted.
But hierarchy isn't rigid or fixed. It's fluid and dynamic, with levels constantly interacting and influencing one another. A change at one level can ripple across the entire hierarchy, transforming the system in unexpected ways.
Voters want to hear about policies that will have an immediate positive impact on their lives. Most have less interest in policies that won't have any obvious benefits for years or even generations. As Niall Ferguson writes in Civilization, "We love our grandchildren. But our great-great-grandchildren are harder to relate to."
One of the challenges of leadership is aligning incentives. How do you get people to move in the same direction without being way-laid by immediate reward? Sun Tzu suggested more than two thousand years ago that a good leader "leads his men into battle like a man climbing to a height and kicking away the ladder." When you can't go back, you motivation is to go forward together.
The acceptance of an initial incentive creates a psychological state whereby we become invested in maintaining whatever story brought about that incentive, so we can justify our acceptance of it.
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 ten million different moves but instead rapidly choose the two or three that are most likely to work.
Heuristics are shortcuts and thus require us to expend less energy. The results may not always be the best (they usually aren't), but they are often good enough for whatever situation we are in. In a process known as "satisficing," we'll often search for the first thing in our brain that satisfies our minimum acceptable conditions. This saves time and energy, but it doesn't mean we get the best outcome.
How to Avoid Anchoring or Recency Bias: Always go back to the base rates and then ask if this new information you have could affect those rates substantially enough for you to change your guess.