First Principles Thinking

by

Want to Learn Faster and More Deeply? Here Is a Mental Model Used by Famous Tech Entrepreneurs, Philosophers, and Physicists.

What does Elon Musk, Jeff Bezos, Immanuel Kant and Richard Feynman all have in common? They all use the same mental model for deep learning and solving complex problems: First Principles Thinking.

What’s awesome about this model is that it disregards all assumptions and gets to the heart of the matter.

It allows you to reduce a concept to it’s core foundational components.

Let’s dive in. And for further reading, Farnam Street has a great detailed chapter on this concept, as well as on the details below on techniques for determining First Principles.

First, let’s talk about what a First Principle is, and how you know you’re thinking in First Principles.

What Is a First Principle and How Do You Know You’re Thinking in One

Step 1: Deconstruct

First Principle Thinking is all about breaking concepts down to their core parts.

They are the building blocks of a skill, idea or discipline.

They are the fundamental components that all the other parts of a concept are built on.

  • They are the punches, kicks and holds in Martial Arts
  • They numbers and operators in math
  • It’s physics in architecture and engineering

Once you get to a core component of something that can’t be reduced any further, you have arrived at a First Principle.

This is important because First Principles avoid assumptions or bias that might block you from solving something.

It’s also important as if you learn the fundamentals in a discipline, you gain a strong foundation in building up a skill.

Step 2: Test

How do you know you’ve arrived at a First Principle?

You test it: challenge it, then reconstruct it.

If the principle you are inspecting cannot be reduced any further, you’ve arrived at a First Principle.

If you land on a statement that is a falsifiable fact, you have a First Principle.

A falsifiable fact has the capacity to be proven wrong. It has no dependencies or biases. But there is a clear way to test whether the statement is right or wrong.

Step 3: Reconstruct

Now it’s time to apply your First Principle to a more complicated problem, or a collection of other First Principles for skill acquisition.

You must reconstruct your problem with these First Principles in mind, then experiment.

Example

Let’s run through an example from start to finish:

Let’s say you want to improve the design of a bicycle wheel.

  1. Identify the fundamental components:
    • The wheel rim
    • The spokes
    • The hub
    • The tire
    • The axle
  2. Break down the problem into basic principles:
    • The wheel rim must support the tire and distribute the rider’s weight.
    • The spokes must connect the rim to the hub and maintain structural integrity.
    • The hub must allow the wheel to rotate smoothly on the axle.
    • The tire must provide traction and cushioning for a comfortable ride.
    • The axle must support the wheel and allow it to rotate.
  3. Challenge assumptions:
    • Why does the rim have to be circular? Could it be a different shape?
    • Do we need spokes, or is there a more efficient way to connect the rim and hub?
    • Can we improve the hub design to reduce friction and increase durability?
    • What if we explore different tire materials or designs?
    • Is there a way to make the axle lighter or stronger?
  4. Reconstruct the solution based on these principles:
    • You might decide to experiment with a non-circular rim shape to improve aerodynamics or weight distribution.
    • You could research new materials and manufacturing methods to replace traditional spokes.
    • Redesign the hub to incorporate advanced bearings or materials for smoother rotation.
    • Investigate alternative tire designs or materials to enhance performance and comfort.
    • Explore high-strength, lightweight materials for the axle.

Here, you’ve deconstructed the elements of a bicycle wheel, and why those elements are important. Then you test the assumptions of the principles, then reconstruct those principles into experiments to attempt to arrive at a better design.

Note that you may even have to challenge very basic assumptions (ex: does a wheel have to be circular) to be sure you’ve arrived at core foundations of a problem, concept or skill.

Okay, now let’s go over some methods for how you can deconstruct a concept into it’s First Principles.

How to Establish First Principles

Method #1: The Five Whys

The Five Whys is a well known strategy for breaking something down. And it is especially effective in getting to a First Principle.

The concept is simple—repeatedly ask why. Every time you answer the “why”, ask “why?” again.

Repeat this process until you’ve landed on a statement of falsifiable fact, and something that can’t be reduced any further.

If you land on a statement that says “that’s just the way it is”, you’ve landed on an assumption based on culture or dogma, not a First Principle. This needs further inspection.

Method #2: Socratic Questioning

From the well-known Ancient Greek philosopher, Socratic questioning follows this process:

  1. Clarify your thinking—what do you think and why do you think it?
  2. Challenge your assumptions
  3. Provide evidence to support arguments
  4. Consider alternative perspectives
  5. Explore consequences and implications of being wrong
  6. Question the original questions

First Principle Thinking has many applications—from learning complex skills to breaking down complicated, seemingly unsolvable problems in more simplified chunks.

It’s a skill that takes a lot of practice (it’s tempting to just rely on assumptions), but pays off the more you do it.

Further Reading: