Why: First Principles

wooden tree trunk emoji on a light brown background

Why: [Topic] is a series of me finding an interesting topic, doing some research, and sharing what I learned. It’s an opportunity for me to follow my curiosity and be skeptical.

Also, since I’m a designer, sometimes I may explore how this topic can benefit designers.

And today, we’re going to learn about First Principles.

What are first principles


First principles are the building blocks of an idea. It’s something that we know is fundamentally true. It cannot be argued or broken down further.

All great scientists and philosophers have used and use first principles. This includes Aristotle, Charlie Munger, and Elon Musk.

Currently, no one embodies first principles more effectively than Elon Musk. I’ll go over his example later.

But first, let’s go over some notable concepts.


Breaking down layers

To think in first principles, you need to break things down.

So, as mentioned in this video, let’s break down an essay.

A breakdown of an essay looks like this:

  • Paragraphs - series of sentences
  • Sentences - series of words
  • Words - series of letters
  • Letters

As you can see, letters are the building blocks of an essay.

A diagram breaking down an essay into paragraphs, sentences, words, letters

And that’s the first important concept of first principles - breaking down ideas. I’ll come back to this essay example later.

Think like a scientist

First principles is a fancy way of saying “think like a scientist.”

Scientists don’t assume anything. They ask:

What are we absolutely sure is true?

Then, they build their ideas on top of these truths, come up with a hypothesis, and test it.

To get more specific, Elon Musk once said:

I tend to approach things from a physics framework. Physics teaches you to reason from first principles rather than by analogy.

I already forgot everything I learned in physics. But, it seems like it’s impossible to defy physics. That’s why Elon Musk uses a physics framework.

But wait! What does he mean by analogy?

Great question. Let’s break it down.

First principles vs analogies

When I researched the first principles, I came across the term “analogy.” Turns out, it conflicts with first principles.

An analogy is how the majority of people live their life.

This Farnam Street article explains this well. I’ll try to summarize it.

You see - Most people have dreams and what they want to achieve in life. But, we often let people tell us what’s possible. And when that happens…

We outsource our thinking to someone else. We start to think like them. We start to use their analogies, conventions, and possibilities.

We become followers of common thoughts.

Now, living by analogy isn’t bad. But, if your goal is to invent something innovative, you should start to move away from it.

Or else, you will start saying

We’ll do that because it’s always been done that way.

Or you’ll not try something because

Well, nobody’s ever done that, so it must not be good.

And to Elon Musk, that’s a ridiculous way to think.

You have to build up the reasoning from the ground up—“from the first principles” is the phrase that’s used in physics. You look at the fundamentals and construct your reasoning from that. And then you see if you have a conclusion that works or doesn’t work.

Chef vs cook

On the note of Elon Musk, let’s talk more about him a bit.

He is an insane human being.

Now, I am aware that he is extremely controversial. For example, the way he treats people is cold-blooded and merciless. His online chat with Halli, a legendary designer, took Twitter by storm.

 Haraldur “Halli” Thorleifsson in the middle of the street on a wheelchair
Read more about Halli vs Musk here

But, I want to focus on his ability as a human being. He is doing so many innovative things that it’s hard to count. Innovative as in doing things that are never done before.

How does he do it?

Well - it’s first principles. And to understand this, I particularly like Tim Urban’s “chef vs cook” concept.

As Tim says:

The difference between the way Elon thinks and the way most people think is kind of like the difference between a cook and a chef.

In short, a “chef” invents a recipe from scratch. And a “cook” follows recipes.

Now, what’s the underlying difference?

A cook works off of some version of what’s already out there. It can be a recipe, a meal she tried before, or a dish she says someone make.

But a chef is different.

She realizes that there’s a layer beneath all those: the raw, edible ingredients. And those are the chef’s first principles. These are her LEGO blocks. And she’s able to invent recipes by experimenting with the ingredients.

The culinary spectrum showing the difference between a chef and a cook
The culinary spectrum from waitbutwhy

Example of first principles

Now, enough theory. Let’s walk through a specific example.

Elon Musk & rockets

This is a pretty famous example. You can watch Elon talk about it in this video.

In the early days of SpaceX, he ran into a major problem.

Rockets are damn expensive - up to $65 million.

This is a huge problem for Musk who want to send people to Mars. So, he began to rethink the problem with the first principles.

First, he asked himself:

What is a rocket made of?
Hm… Aerospace-grade aluminum alloys, plus some titanium, copper, and carbon fiber.

Then, he asked:

What is the value of those materials on the commodity market?

It turns out

The materials cost of a rocket is around 2% of the typical price.
wow gif of a man flipping his sunglasses up

So, he decided to build his rocket at a much cheaper price.

If Elon just took for granted what the rocket costed before, he would never solve this problem. It was because he looked at the first principles - the materials of a rocket - that he came to this conclusion.

Now, if you want to see more examples, check out this article.

Using first principles

At this point, you might be wondering

So… how can I actually use first principles? And what for?

It seems like, thinking in first principles has two clear benefits:

  1. Solve complex problems
  2. Build something new

For the first benefit, Elon Musk’s rocket is a great example. But for the second benefit…

How can I use first principles to build something new?

Well, remember our essay example? In the beginning, we broke down an essay into

  • Paragraphs - series of sentences
  • Sentences - series of words
  • Words - series of letters
  • Letters

Now, we know the different components of an essay. The magic is: We can now rearrange, change, or put them together differently to create a new idea or product.

For example, let’s add another layer on top of essays. We’ll call this a book - a collection of essays.

Viola! We’ve created something new!

And this method of breaking things down and creating hierarchies can be applied to everything else.

Lessons for designers

Now, let’s see how product designers can benefit from thinking in first principles.

Way of viewing the world

I believe all product designers should have a healthy level of skepticism about this world.

Learning about first principles helped me understand what I don’t want to do:

Getting used to following other people’s beliefs.

This reminds me of Tony Fadell’s TED talk.

In the talk, Tony talks about a double-edged sword: habituation. In one way, habituation is good because it frees up space for you to learn new things.

But, it’s bad because it stops us from noticing the problems around us. We get used to our surroundings. And when people notice a problem, we say

Oh, it’s fine. That’s just how things work here.

As a designer, we should always be skeptical about this world. Do not take things for granted.

Always asking why to break down problems

If you’re a designer, you’ve probably heard of “Five Whys.

It’s as it sounds:

Asking “why” five times to expose root causes and explore effective solutions.

Turns out, the “Five Whys” aligns with the essence of the first principles:

Understanding how things actually work.
Flowchart showing the 5 whys method

Thus, as you notice or hear something from the user, delve deeper. Ask them why. Maybe not directly five times. But it’s the spirit that counts.

Be conscious of your assumptions & document

As designers, we often make assumptions, consciously and subconsciously, quickly.

It’s fine to have assumptions. We do it all the time.

But, when you blindly follow your assumption, that’s not good.

Thus, It’s important to be conscious of your assumptions. Ask yourself these questions

  • Why do I think this?
  • How do I know this is true?
  • How can I back this up?

If you’re unsure of anything about the assumption, that’s when you should test it. This can be done in the form of user research (interviews, surveys, observations, etc). Or, if you have limited time, creating a quick MVP and testing works great too.

The point of this is that we want to get as close to the truth as possible and move away from our assumptions.

Knowing that

Hey! This is an assumption I made! Let me delve deeper / test it out.

is a great first step.

Also, I’ll recommend you to keep a “design doc” to record design rationales & assumptions. You’ll thank yourself for this when creating your case study.


So, that was the first article of the series of Why: [Topic] on first principles.

I hope you learned something new from this article. I sure did.

To wrap up this post, I want to end with this:

Don’t let others think for you. Use first principles to form your understanding of this world.

And that’s a wrap!

Thank you for being awesome and reading this far! :)

If you have any questions, feel free to reach out on LinkedIn, Twitter, or by email. Will love to set up a casual call and chat!

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