First principles are the foundation from which any other action or insight is derived from. You can uncover them by asking “why” or using a Socratic type of questioning. You know you’ve got a first principle if you can’t deduce it from other principles.

Thinking from first principles means starting from a basis without assumptions or beliefs. Hence, it’s the best starting point for any solid argumentation or deduction. It avoids incorrect beliefs early on and is a robust way of thinking.

Because it removes commonly held beliefs it’s a great way of recombining and essentially rebuilding thought constructs. This often opens up completely new creative possibilities because you don’t automatically follow the path everyone else is.


Cognito Ergo Sum

René Descartes conducted a famous thought experiment. He imagined that an evil demon was trying to trick him into believing things that weren’t true.

“I shall think that the sky, the air, the earth, colors, shapes, sounds and all external things are merely the delusions of dreams which he has devised to ensnare my judgement. I shall consider myself as not having hands or eyes, or flesh, or blood or senses, but as falsely believing that I have all these things.”

He realized that he could question almost everything about his perception. So what could he know then? After questioning everything he knew and experienced, Descartes realized that there was one undeniable thing: His thought. All his doubting and thinking lead him to his famous quote “Cogito ergo sum” – I think therefore I exist. Descartes discovered a first principle:

Let the evil demon do his worst, but from the very fact that I am thinking, doubting, being misled, it necessarily follows that I exist!

From that basis, he started to build his philosophy and made big contributions to the field.

Scientific Process

Another example is the scientific process in general. Good science avoids assumptions. Scientists go to great lengths to build hypotheses and then systematically. They then verify them step by step through experiments. This process of observation, hypothesis, making a prediction, conducting an experiment, and finally, analyzing the result, is a systematic way to uncover first principles.


Blasting away assumptions and beliefs

Socrates wasn’t exactly the most beloved citizen of ancient Athens. He bothered people with his nagging questions that questioned their beliefs. Socratic questioning is a method that can be used for uncovering first principles.

Go to the bottom of your thoughts and figure out where they came from. Explain to yourself why you think what you think and challenge yourself on it. An easy way to arrive there is by asking “Why” repeatedly. Children do this a lot to understand the world. Asking “Why” five times forces you to confront some of your assumptions and gets you closer to the underlying principles. Find evidence for your view that supports it. But also look for different perspectives that question it.

Here are some cases where questioning your assumptions and beliefs is useful:

  • in science to produce valuable and unbiased research
  • in investing to make sound decisions that are rooted in reality and not wishful thinking
  • in business, by selling what customers actually want instead of what you think they want
  • in your personal life by questioning the deeply held beliefs that hold you back.


The other place where first principles thinking is highly valuable is when you want to uncover new perspectives and ways of doing things.

Starting from the root of a tree you’ve got many more possible branches you could end up with than if you start on a later branch fork. The further up you choose your starting point the more limited the branches you can go down. You’ll likely arrive at the same places as others starting from that branch before you.

Instead, go back to the root, the first principles, and build your thoughts step by step from there. You’ll be far less limited by false beliefs and you’ll end up at places that nobody thought possible.


First principles are relative to the status of our knowledge. Based on your limited knowledge in different fields, first principles might look different to you than an expert. Because of the problem of induction, we can never arrive at Truths with a capital “T”, Karl Popper showed us that. But we can get close by creating and learning knowledge that stood the test of falsifiability over time. Even going one or two levels deeper than most will yield immense benefits.

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The fundamental building blocks upon which everything else is built. The foundation comes first and is built strong so that whatever construction is put on top holds even in the most extreme weather.