First Principles Thinking
First principles thinking is the practice of breaking down a problem into its most fundamental truths and reasoning up from there, rather than reasoning by analogy or convention.
Elon Musk famously used this approach when building SpaceX. Instead of accepting that rockets must cost tens of millions of dollars, he asked: "What are rockets made of? What do those raw materials cost on the commodity market?" The answer revealed that materials were only about 2% of the typical price.
How to Apply It
- Identify your assumptions about a problem
- Break those assumptions down to fundamental truths
- Reason up from the fundamentals to create new solutions
A colleague's vendor evaluation in link not tracked is a good example of what happens when you skip first principles — she defaulted to benchmarking against competitors instead of asking what the actual requirements were.
First principles thinking pairs well with Inversion — once you have your fundamentals, invert the problem to find hidden obstacles. It also connects to Occam's Razor: the simplest solution built from fundamentals is often the best.
See also: Mental Models Overview for how this fits alongside other models.