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First Principles

Strip away assumptions. Reason from fundamentals.

The first principle of first principles: How do you name and categorize things by their purpose? This is nomenclature (naming) and taxonomy (classification). Without naming standards, you can't decompose to fundamentals — you don't know what you're looking at.

What It Is

The ability to decompose problems to their most basic truths, then rebuild understanding from scratch. Not "how is it done?" but "what must be true?"

Why It Matters

Most thinking is analogy — copying what others did. First principles thinking creates what didn't exist. It's how breakthroughs happen.

Reasoning by AnalogyReasoning by First Principles
"This is how it's done""What's actually required?"
Incremental improvementStep-change innovation
Constrained by precedentConstrained only by physics
Fast but localSlow but global

Core Patterns

  • Decompose — What are the irreducible parts?
  • Question constraints — Is this actually a rule or just convention?
  • Physics test — Does it violate laws of nature?
  • Rebuild — Given only fundamentals, what's the best solution?
  • Simplify — Remove until it breaks

How to Develop

  1. Ask "why?" five times — go to the root
  2. Identify hidden assumptions — list what you're taking for granted
  3. Study different industries — see the same problem solved differently
  4. Build from scratch once — understand what you've been outsourcing
  5. Embrace "I don't know" — not-knowing is the start

Method

"The first basis from which a thing is known." — Aristotle, Metaphysics

The cognitive process for reasoning from fundamentals:

StepActionQuestion
1Identify assumptionsWhat do I believe is true? List every constraint.
2Decompose to fundamentalsWhat are the irreducible components?
3Rebuild from scratchGiven only these truths, what's optimal?

Techniques:

  • Five Whys — Ask "why?" until you hit bedrock truth
  • Socratic questioning — Disciplined dialogue that exposes assumptions
  • Physics test — Does it violate natural laws? If not, it's possible.

Example: SpaceX rockets. Industry price: $65M. Musk asked: "What are rockets made of?" Aluminum, titanium, copper, carbon fiber. Raw materials = 2% of price. Built in-house. Cut costs 90%.


Systems Engineering

Musk's 5-step algorithm for manufacturing optimization. Steps must be done IN ORDER.

StepActionPrinciple
1Question requirementsYour requirements are definitely dumb
2Delete parts/processesIf you don't add 10% back, you didn't delete enough
3Simplify & optimizeDon't optimize what shouldn't exist
4Accelerate cycle timeDon't dig your grave faster
5AutomateOnly automate what survived steps 1-4

Most engineers start at step 5. That's the mistake.

Archetypes

Primary: Philosopher — seeks fundamental truths Secondary: Engineer — applies principles to build

Context