Most of us think by analogy. We look at what others are doing, what has been done before, and we make small improvements. This is a path to incremental change, not innovation. It is craft without art.
First principles thinking is the alternative. It is a powerful mental model for breaking down complex problems to their most basic elements, the foundational truths, and building new solutions from there. It is the method scientists and inventors use to find hidden knowledge and create something new.
This guide provides a systematic framework to shift your thinking from analogy to first principles. It is a process for finding the truth of a situation so you can build your solutions on a foundation of rock, not sand.
Put This Framework Into Practice
This article is the map. To help you navigate the territory, we’ve created The First Principles Inquiry—a free, duplicatable Notion workspace. It contains all the frameworks and exercises from this guide, structured for your own deconstruction and self-inquiry.
[→ Get the Free Notion Workspace Here](/requests/first-principles-inquiry)
## What is First Principles Thinking?
A first principle is a foundational proposition or assumption that cannot be deduced from any other proposition or assumption. In science, theories and laws are derived from first principles. In mathematics, axioms are the first principles.
Aristotle, one of the first to articulate this method, stated:
> "In every systematic inquiry (methods) where there are first principles, or causes, or elements, knowledge and science result from acquiring knowledge of these; for we think we know something just in case we acquire knowledge of the primary causes, the primary first principles, all the way to the elements." — Aristotle
The idea is to find a way to the elements (truth, essence) with the method of first principles. It should start with an idea or a problem and go back until an axiom or a first principle is found. To do so it's essential to find the right questions to ask to decompose the problem and build up from the foundation.
In other words, first principle method is to question an assumption until you find the essentials and the truth.
In Pixar, whenever the filmmakers present a derivative (made by analogy) story to John Lasseter, he often tells them to stop and do their research. That is why all the films they produce are original and creative.
> "When filmmakers, industrial designers, software designers, or people in any other creative profession merely cut up and reassemble what has come before, it gives the illusion of creativity, but it is craft without art.” Cal Newport, Creativity Inc.
Thinking by analogy is a way to mediocrity and stagnation. Innovations and progress are based on unique knowledge that is found by reasoning from first principles.
## First Principles Thinking vs Thinking by Analogy
There are many comparisons between analogous and first principles thinking. The [coach](https://fs.blog/2018/04/first-principles/#:~:text=A%20first%20principle%20is%20a,writing%20on%20first%20principles%2C%20said%3A&text=Reasoning%20by%20first%20principles%20removes%20the%20impurity%20of%20assumptions%20and%20conventions.) and the play stealer, the [chef](https://waitbutwhy.com/2015/11/the-cook-and-the-chef-musks-secret-sauce.html) and the cook, or the [architect](https://www.maray.ai/posts/the-guide-to-architects-career-path) and the draftsman. You can see the hint. The former build something unique and the latter follow instructions.
Since ancient times knowledge and wisdom were passed down from a generation to another. Things did not change much, and it was not encouraged to take risks and think differently.
In the fast-changing world, it is safer now to explore and take risks. If we want to discover something new, we have to shift the way we think and ask questions to find something insightful and secret.
> First principles thinking: is it true?
> Analogous thinking: it was done before, therefore, it is true.
A lot of products, projects, and businesses are designed by analogy. They bear an incremental improvement and change to existing ideas. It comes to mixing features and properties. The focus is on the form.
For instance, when architects design spaces, they use projects built before them as a basis for their work. There are several reasons for this. First, buildings are complex and expensive entities. To justify a decision, you need proof that a solution has worked before and it will work in the future. Second, it is the easiest thing to do. Take several successful projects, mix them and you have something "new". Third, most of the architects, and people in general, were not taught how to design from the ground up.
Companies like SpaceX are built from the ground up. Elon musk took an existing problem, deconstructed it, got rid of assumptions, and built up the idea from its foundation.
To shift your thinking from analogy to First Principles, you have to deliberately practice and integrate frameworks into your thinking.
## How to Practice First Principles Thinking: A 3-Step Framework
This simple, three-step framework is the engine of first principles thinking. It provides a reliable process for moving from a surface-level understanding of a problem to its core truth.
### Step 1: Identify and Question Your Current Assumptions.
What do you *think* you know about the problem? What is the conventional wisdom? List every assumption, every belief, every "best practice." Then, challenge each one. Why is it done this way? Is this truly a law of nature, or is it a historical artifact, a preference, a tradition?
### Step 2: Deconstruct the Problem into its Fundamental Truths.
Break the problem down into its most basic, indivisible elements. If you were building a rocket, you would ask: What is a rocket made of? You would arrive at the raw materials: aluminum alloys, titanium, copper, carbon fiber. Then you would ask: What is the market value of these materials? This process strips away the high price tag of the finished product and reveals the foundational cost of its components.
### Step 3: Rebuild Your Understanding from the Ground Up.
Once you have a foundation of solid, undeniable truths, you can begin to build a new, more effective solution. By knowing the raw material cost, you can devise a radically cheaper way to build a rocket. You are no longer iterating on an old design; you are creating something new from the source.
## 3 Questioning Methods to Apply First Principles
The 3-step framework tells you what to do. These mental models tell you how to do it. They are practical tools for questioning assumptions (Step 1) and deconstructing problems (Step 2).
### 1. Five Whys Framework
Children are natural first-principles thinkers. They ask "why" relentlessly until they reach the foundation of a concept. This model replicates that simple, powerful process. When you encounter a problem or a belief, ask "Why?" five times to drill down past the symptoms to the root cause.
*Problem:* I am procrastinating on this project.
1. *Why?* Because I feel overwhelmed.
2. *Why?* Because the first step feels too big.
3. *Why?* Because I'm not sure if I'm doing it right.
4. *Why?* Because I'm afraid of producing mediocre work.
5. *Why?* Because I believe my work is a reflection of my self-worth.
Truth: The root cause is not laziness; it is a fear of judgment tied to identity. The solution is not a productivity hack; it's to address that fear.
### 2. Socratic Questioning
1. **Clarify your thinking:** *Why do I think this? What, exactly, do I believe?*
2. **Challenge assumptions:** *How do I know this is true? What if I'm wrong?*
3. **Look for evidence:** *What are my sources? Is this data reliable?*
4. **Consider alternative perspectives:** *What might others think? How can I be certain?*
5. **Examine consequences:** *What are the implications if I am right? What if I am wrong?*
6. **Question the original question:** *Why was this question important? What have I learned from this process?*
It helps to figure out several important things. First, find the origins of your idea. Is it based on your assumptions? Can you find data to prove its viability? Second, consider symmetrically different perspectives to understand possible consequences. Lastly, conclude and move up from there.
### 3. Elon Musk's Frist Principle Reasoning Framework
Elon Musk was one of the first to popularize the First Principles reasoning. This approach led him to discover opportunities for his new companies SpaceX and Tesla, which made him the richest person in the world in 2021.
It was not until Elon started up SpaceX when the whole aerospace industry shifted. Before, every company took an approach of incremental change and improvement before his intervention. The existing technologies have been improved and tinkered with since the mid of the 20th century.
To gain insight, he asked the following questions.
- What are the problems?
- Why is it expensive?
- What can I do differently?
- What do we know is true?
- What are the obstacles?
Nobody assumed to reduce the cost of rocket production and launches. First principles reasoning led him to discover that production cost can be significantly reduced. He deconstructed the problem into its foundational principles and built his solution from the bottom up.
**Elon Musk's 3-step framework**
1. Identify current assumptions.
2. Break down the problem into its fundamental principles.
3. Create new solutions from the discovered truth.
This framework provides a solid structure to deconstruct a problem and test different solutions. If you have an idea, try to apply Elon's framework to gain insight and find secrets that thinking by analogy would not allow.
## 5 First Principles Thinking Exercises to Build Your Skill
Knowledge is not enough. You must practice. Here are five exercises to move from theory to application.
1. **The Assumption Reversal:** Take a common belief in your industry (e.g., "You need a university degree to succeed"). Spend 15 minutes writing a strong argument for the exact opposite. This forces you to challenge ingrained assumptions.
2. **The Component Breakdown:** Pick a simple object on your desk, like a coffee mug. Deconstruct it. What is it made of? How much does the raw ceramic cost? What was the cost of the energy to fire it? The labor to form it? The logistics to ship it? This trains you to see the true cost behind the perceived price.
3. **The "5 Whys" Self-Inquiry:** The next time you feel a strong negative emotion (anger, frustration, anxiety), stop. Take out a piece of paper and apply the "5 Whys" framework to that feeling. Be ruthlessly honest. What you’ll discover is remarkable.
4. **Redesign a Daily Object:** Choose a common object like a chair or a toothbrush. Ignore its current form entirely. Start from its fundamental purpose (e.g., "to support a human body in a resting position"). Design a new solution from that truth.
5. **Deconstruct a Service:** Take a modern service like Uber or Spotify. Break it down into its core functions (e.g., Uber: Request a ride, Match driver, Route navigation, Process payment). This reveals the simple engine inside the complex brand.
## First Principles in Action: Real-World Examples
- **SpaceX:** The aerospace industry reasoned by analogy, assuming rockets had to be expensive. Elon Musk started from first principles, calculated the raw material cost of a rocket (which was only 2% of the typical price), and engineered a new, far cheaper solution by bringing manufacturing in-house and building reusable rockets.
- **Pixar:** Many animation studios reason by analogy, replicating past successful formulas. Pixar's leadership forces filmmakers to start from a place of deep, original research and a core emotional truth. This commitment to first principles is why their stories feel authentic and consistently break new ground.
## Final thoughts
Thinking by analogy is comfortable. It's safe. It is also the path to mediocrity.
First principles thinking is a discipline. It requires you to dismantle what you think you know in order to discover what is actually true. The framework and exercises in this guide are not just intellectual tools; they are a practice for achieving clarity.
Start with one exercise. Deconstruct one assumption. The goal is not to become an inventor overnight, but to build the habit of questioning, digging, and reasoning from a place of truth. That is the only foundation upon which a truly original life and work can be built.
[→ Get the Free Notion Workspace Here](/requests/first-principles-inquiry)
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## FAQs About First Principles Thinking
### What is first principles thinking?
First principles thinking is a method for deconstructing a problem into its most fundamental, undeniable truths. Instead of building on existing assumptions (analogy), you reason up from a foundation of truth to create a new, more effective solution.
### What does Elon Musk mean by first principles thinking?
For Elon Musk, it means boiling things down to their fundamental physics. He ignores the existing price of a product (like a rocket) and instead calculates the raw material cost of its components. By reasoning from that "first principles" cost, he can engineer a radically cheaper way to build it.
### What is the opposite of first principles thinking?
The direct opposite is <strong>reasoning by analogy</strong>. This is the default way most people think: looking at what has been done before and making small improvements or variations. It leads to incremental change, not true innovation.
### Is first principles thinking hard to learn?
The concept is simple, but the practice is challenging. It requires the discipline to question your own deeply-held beliefs and the courage to think differently from the crowd. It is less of a skill to be learned and more of a habit of rigorous self-inquiry to be developed.
### Who are some famous first principles thinkers?
Besides Elon Musk and Aristotle, figures like inventor Johannes Gutenberg, scientist Marie Curie, and investor Charlie Munger are all examples of individuals who succeeded by deconstructing the conventions of their fields and reasoning from foundational truths.
### How do you practice and develop first principles thinking?
Developing this skill is a consistent practice, not a single event. It involves two core activities:
1. Apply the Framework: Regularly use the three-step process of identifying assumptions, deconstructing the problem to its fundamental truths, and rebuilding a solution from there.
2. Use Practical Exercises: Intentionally use methods like the "Five Whys" or Socratic questioning to build the mental habit of digging past surface-level answers to find the root cause.
### Where can I find a first principles thinking book pdf?
While this guide is not available as a downloadable PDF, it provides a complete framework for applying the method. For a practical, hands-on resource to put these ideas into action, you can use my free [First Principles Inquiry Notion workspace](/requests/first-principles-inquiry). It contains all the exercises and systems discussed in this article.
