Published on Jun 07, 2020

Reasoning from First Principles


Over two thousand years ago, Aristotle defined a first principle as “the first basis from which a thing is known”. This is not a post about how the Greeks invented everything (although I can make the case for it) but rather a post about learning and a mental model that is tremendously useful. Put more simply, reasoning from first principles is the act of breaking down complicated problems into basic elements and then reassembling them from the ground up. By building a strong foundation of a subject, you can reason up from there and create a good feedback loop.

Becoming part of culture

The term first principles has become quite popular over the past decade or so. Silicon Valley in particular has appropriated the term – just listen to any tech podcast. The most famous person advocating for first principles reasoning is Elon Musk. He’s used this form of reasoning to disassemble complicated engineering problems and convert them into world changing businesses. For instance, his rocket ship company SpaceX is successful, not only for its innovation but for its low cost structure. Elon looked at the supply chain of building rockets and saw enormous glut. There were many suppliers all taking margin over one another which resulted in exorbitant prices for rockets. The company centralized production and built a vertically integrated structure. Arguably, SpaceX’s biggest innovation was to bring down the cost of rockets. If you are a country looking to send a satellite in space, it costs one tenth less to hire SpaceX to do it for you.

Many of the world’s greatest innovations usually start with something hiding in plain sight. It just takes someone to look at the problem and deconstruct it.

How this has helped me

I’ve found that when I’ve tried acquiring a new skill that is foreign to me (hello corporate finance), I need to start with the basics and just learn them over and over again. It may sound simple but learning the foundations well of any subject is not as easy as it seems. Before moving on to more advanced material, I always try to relate back to the basics of the subject/skill at hand. I’ve also created cheat sheets with guiding principles on different subjects that helps me keep track.

At work, a useful framework we’ve been using is Wardley Mapping. You begin by breaking down something into its core components and place them along the value chain. It’s tremendously useful for being able to dissect almost any subject and formulate effective strategies.

Why it’s relevant today

As more variables get introduced into the equation, you can argue that increased complexity is becoming the norm. Reasoning from first principles can be a great starting point to identify original solutions to wicked problems.

Apart from building spaceships or saving the world, it’s also a great way to learn and get better.

Great reads on the subject

First Principles: The Building Blocks of True Knowledge – Farnam Street

Aristotle and the Importance of First Principles – Aly Juma

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