Mark: The French army in 1940 had more soldiers, more tanks, and better artillery than the Germans. Yet, they were catastrophically defeated in six weeks. The reason wasn't brute force; it was a failure to understand a basic law of nature that governs us all. Michelle: Whoa, hold on. More of everything and they still lost that badly? That sounds completely backwards. How does a superior force just collapse like that? Mark: It’s a perfect, if tragic, example of the ideas in the book we’re exploring today: The Great Mental Models, Volume 2: Physics, Chemistry, and Biology by Rhiannon Beaubien and Shane Parrish. Michelle: Right, and this isn't just some dense science textbook. The authors have a fascinating background—Beaubien, for instance, comes from the world of Canadian intelligence. They're all about taking these huge, complex ideas from science and turning them into practical tools for thinking, which is probably why the series has been so widely acclaimed. Mark: Exactly. They argue that the fundamental laws of the universe can explain almost everything, from why relationships fail to why businesses go bankrupt. And the first fundamental law they tackle is one that messes with our most basic assumption: that what we see is real. It all starts with Einstein and a train.

Michelle: Okay, I’m bracing myself. Whenever Einstein and a train are in the same sentence, my brain starts to melt a little. Mark: (Laughs) Stick with me, it’s worth it. Imagine a train moving at a very high, constant speed. You, Michelle, are standing on the ground next to the tracks. I’m a passenger on that train, sitting exactly in the middle. Just as my midpoint passes you, two bolts of lightning strike the train—one at the very front, and one at the very back. Michelle: Okay, so lightning hits both ends of the train at the same time. Mark: From your perspective on the ground, yes. You're standing equidistant from where the two strikes hit, so the light from both flashes reaches your eyes at the exact same moment. You would swear, under oath, that the strikes were simultaneous. Michelle: Makes sense. Mark: But what do I see from inside the moving train? Because I'm moving towards the light from the front strike, and away from the light from the rear strike, the light from the front has less distance to travel to reach my eyes. So, I see the front of the train get hit first, and then a moment later, I see the back of the train get hit. Michelle: Wait a minute. So I see them happen at the same time, and you see them happen at different times. Who’s right? Mark: That’s the genius of it. According to Einstein's theory of relativity, we both are. There is no single, absolute truth about the timing of the event. Our perception of reality is dependent on our frame of reference—in this case, whether we are stationary or in motion. Michelle: Hold on. You're saying two people can see the exact same event, and their descriptions of when it happened are both right? That feels impossible. My brain is officially protesting. Mark: It’s a wild concept, but it has profound implications. The book quotes someone who says relativity is founded on a kind of scientific empathy. It forces you to imagine how the world appears to someone moving differently than you are. Michelle: Wow. So this is the physics behind the Rashomon effect! The famous movie where a crime is shown from four different viewpoints, and they're all contradictory. This isn't just about bias or people lying; their physical reality could actually be different. Mark: Precisely. The book brings up the real-life legal case of Minh Hong, who was on trial for a death that occurred during a chaotic brawl. The eyewitness testimonies were a mess. People swore they saw things that were physically impossible from their vantage point. Their emotional state, their relationship to the victim, their physical location—all of it created different, conflicting "truths." Michelle: That’s incredible. It completely changes how you think about arguments or disagreements. You assume you're debating a shared set of facts, but you might be operating in fundamentally different realities from the very start. Mark: And that’s just the first model. It gets even bigger. Michelle: Okay, so our individual reality is subjective. That's unsettling. But what about the shared world we all live in? It feels like things are constantly breaking down, from my to-do list to big institutions. Is there a universal law for that too?

Mark: There absolutely is. And it’s one of the most powerful and misunderstood laws in science: the Second Law of Thermodynamics. In simple terms, it's the law of entropy. Michelle: Entropy. I know that word. It’s basically the universe’s tendency to get messy, right? Like my office, which seems to generate clutter all by itself. Mark: That’s a perfect analogy. The law states that in an isolated system, disorder—or entropy—always increases. Your clean office is an ordered state. Your messy office is a disordered state. Without a constant input of energy from you—cleaning, organizing—it will naturally slide into chaos. A hot cup of coffee doesn't spontaneously get hotter; it cools down, dissipating its energy until it reaches equilibrium with the room. That's entropy in action. Michelle: So my laziness is just me obeying a fundamental law of the universe. I feel so validated. Mark: (Laughs) You could argue that. But the book scales this idea up to something far more profound. It uses the story of the Berlin Wall. Think about the immense, almost unimaginable amount of energy the Soviet Union had to pour into that system to keep it "ordered." Michelle: What do you mean by ordered? Mark: They were trying to create a perfectly closed system. To stop the flow of people, ideas, and culture from West to East. The wall wasn't just a wall; it was a massive, energy-intensive project. Concrete, barbed wire, armed guards, surveillance, political purges. They were trying to fight the natural tendency of two systems in contact—East and West Germany—to reach equilibrium. To share what the book calls "social heat." Michelle: That's a chilling way to put it. They were fighting a law of physics. It was doomed from the start. Mark: It was. The book has this fantastic quote: "Walls are rarely completely effective." The more energy they put into sealing the border, the more they proved to their own people that the system they were defending was a prison. The desire for freedom, for equilibrium, just built and built until the wall came down. The energy required to maintain that artificial order became unsustainable. Michelle: So for a business or a team, what's the 'energy' we need to put in to fight this decay? Is it just constant effort? More meetings, more processes? Mark: Not just effort, but the right kind of effort. It's about creating structures, a strong culture, shared stories, and a common purpose. Those are the things that combat the natural entropy of an organization. Without them, teams drift, communication breaks down, and the mission fades. You have to actively maintain the order you want. Michelle: It’s like you’re constantly paddling against the current of the universe. Mark: Exactly. It's about putting in the right kind of energy. Which brings us back to that French army in 1940. They had a massive, well-ordered system, but they still collapsed. This is where the laws of biology come in, specifically, the idea of adaptation.

Michelle: Okay, so the French had their organized army, their "low-entropy" system. Why wasn't that enough? Mark: Because the environment around them changed, and they didn't. The book explains this with a concept from evolutionary biology called the Red Queen Effect, which is named after a scene in Lewis Carroll's Through the Looking-Glass. Michelle: I remember this! Alice is running as fast as she can, but the landscape is moving with her, so she's not getting anywhere. Mark: Exactly. And the Red Queen tells her, "Now, here, you see, it takes all the running you can do, to keep in the same place." In biology, this means species have to constantly evolve and adapt not to get ahead, but just to survive, because their predators, prey, and competitors are all evolving too. Standing still means extinction. Michelle: That is a terrifying thought. So all your hard work might just be enough to keep you from falling behind. Mark: Precisely. And this is what happened to France. After World War I, they built the Maginot Line, a massive and technologically advanced series of fortifications. They poured all their energy into perfecting the art of static, defensive warfare. They were preparing, with immense effort, to fight the last war over again. Michelle: But the Germans weren't playing that game anymore. Mark: Not at all. While the French were building concrete bunkers, the Germans, particularly generals like Heinz Guderian, were developing a completely new theory of warfare: the Blitzkrieg, or "lightning war." They focused on speed, surprise, and deep penetration with fast-moving armored divisions. They changed the environment of war itself. Michelle: So the French were perfectly adapted to an environment that no longer existed. Mark: Perfectly. When the German Panzers simply went around the Maginot Line, through the "impassable" Ardennes Forest, the entire French defensive system became irrelevant overnight. Their order and strength were useless because they couldn't adapt. Michelle: So they weren't adapting. Their environment changed, but they didn't. They were running hard, but on a treadmill that was about to be thrown off a cliff. Mark: A perfect summary. And this happens to companies all the time, right? Think of Blockbuster. They perfected the video rental store model. They had low entropy, they were highly organized. But then the environment changed to streaming. They kept running on their treadmill, and Netflix, the new predator, just ran right past them. Michelle: Kodak is another one. They invented the digital camera but were so invested in their film business that they couldn't adapt. They failed the Red Queen's test. It's brutal.

Mark: It is brutal. And when you put these three models together, you get a really powerful, if slightly intimidating, picture of the world. Michelle: Let me see if I can connect them. Relativity tells us our personal view of the world is inherently incomplete and subjective. Mark: Right. Your truth isn't the whole truth. Michelle: Then, Entropy tells us that the external world we all share is constantly, naturally, sliding into chaos and disorder unless we actively fight it. Mark: The universe is fundamentally lazy. Michelle: And finally, the Red Queen Effect tells us that while we're fighting that chaos, everyone and everything else is also adapting and changing, so we have to run as fast as we can just to keep from being left behind. Mark: That’s it. You have these three powerful forces acting on us at all times. Relativity says your view is incomplete. Entropy says the world is tending towards chaos. And the Red Queen Effect says you have to keep adapting to survive in that chaotic, subjective world. Michelle: So what's the one thing we can do? It feels overwhelming. How do you fight all of that at once? Mark: The book offers a beautifully simple, practical answer. It argues that while experience is good, the real key to learning is reflection. And the best tool for reflection is to start a journal. Michelle: A journal? That seems almost too simple. Mark: But it’s about the practice. When you see a situation—a failed project at work, an argument with a partner—try to apply one of these models. Was it a problem of relativity, where two people had different frames of reference? Was it entropy, where a lack of energy led to decay? Was it a Red Queen problem, where you failed to adapt? Write it down. What worked? What didn't? That's how you build what the book calls your own "latticework of mental models." You stop being a victim of these invisible forces and start using them to your advantage. Michelle: I love that. It’s not just about knowing the models, but actively using them to make sense of your own life. It’s a toolkit. We’d love to hear from our listeners—which of these models resonates most with you? The subjective reality, the slow decay, or the constant race? Let us know. Mark: This is Aibrary, signing off.