Why do first principles help students build connections between disciplines, rather than learning in isolation?

Let's take an analogy. The various subjects we study, such as physics, chemistry, and economics, are like ready-made LEGO models built by others: a car, a house, a spaceship.

"Isolated learning" is like getting the instruction manuals for these three models and memorizing them by rote. You know that a "car" needs part A and part B to be assembled, a "house" needs C and D, and a "spaceship" needs E and F. You're good at following the blueprints, but to you, the car, the house, and the spaceship are three completely unrelated things. If you're asked to use car parts to fix a house, you might be stumped because the manual doesn't say anything about it. You're just a skilled "assembler."

What is "first principles thinking"? It tells you to throw away the instruction manuals first, and forget about cars, houses, or spaceships. It asks you to sit down and carefully examine the most basic LEGO bricks in your hand: What is this 2x4 brick for? Oh, it's very stable, suitable for load-bearing walls. What about this part with an axle? It can rotate, suitable for wheels or movable joints. And this smooth, thin plate? Suitable for surface decoration.

Once you understand the functions and combination methods of these most basic bricks (which are the "first principles"), when you look back at that car, that house, and that spaceship, you no longer see three isolated models. You'll discover:

"Oh! The wheels of the car and the rotating radar on the house both use the same 'bearing' principle!" "The smooth exterior of the spaceship and the floor of the house both use the same 'smooth joining' idea!"

You see, the connections are found just like that. You are no longer looking at the "model" as a superficial appearance, but seeing through to their common "building logic" behind them.

Back to academic disciplines. The "Law of Entropy Increase" in physics (things tend to go from order to disorder) and "information entropy" in information theory sound completely unrelated. But viewed through first principles, their essence is both a measure of a system's "degree of disorder." "Supply-demand balance" in economics and "population balance" in ecology, though seemingly different fields, at their core are models of a "dynamic equilibrium system," where if one side increases, the other will change to inhibit it, eventually reaching a relatively stable state.

Therefore, first principles thinking helps you strip away the "facade" of different disciplines (jargon, formulas, specific contexts), allowing you to get straight to their common "core" (basic logic, mathematical models, systemic laws). In this way, your knowledge is no longer a collection of isolated islands, but an interconnected web. When you learn something new, you will instinctively think: "What underlying logic of this thing is similar to something I've learned before?" This ability to draw inferences about other cases from one instance is far more powerful than rote memorization of a bunch of isolated knowledge points.