First Principles Decomposition identifies necessary versus inherited assumptions by recursively asking “why” and categorizing each into physical necessity, logical necessity, convention, or untested assumption.
"What's actually necessary here, and what's just inherited?"
Take a claim seriously enough to dismantle it. Ask "why?" recursively until you reach either physical/logical necessity or pure convention. Most "requirements" turn out to be inherited beliefs — and the unbuilt solutions become visible only after the conventions are named.
- Separates physical and logical necessity from convention and untested assumption
- Surfaces the conventions everyone treated as bedrock
- Generates concrete alternative designs once those conventions fall away
When to Use
When you keep rebuilding the same shape and don't know why. When "we've always done it this way" is doing the heavy lifting in a design discussion. Before committing to a major redesign — to make sure you're not just porting old assumptions into a new container. The method shines when a "requirement" feels load-bearing but no one can quite say what it carries.
How It Works
One role works in three passes:
- The Decomposer (Why-Chain): Asks "why must this be true?" three to four levels deep. At each level, the hidden assumptions get named explicitly. The chain terminates at bedrock, convention, or contradiction.
- The Decomposer (Sort): Goes back through every assumption surfaced and sorts each into one of four categories — physical necessity, logical necessity, convention, untested assumption.
- The Reconstruction: Synthesizes what must stay, what can go, and 2-3 alternative ways the claim could be redesigned if only the necessities remained.
What You Get
A sorted list of necessities vs. conventions, 2-3 alternative reconstructions of the claim, and the "hidden move" — the single convention everyone treated as bedrock that turns out to be droppable, and the design that becomes possible without it.
Related Methods
- TRIZ — when you want to surface dysfunctions through reverse brainstorming instead of decomposition
- Polarity Management — when "conventions" might be invisible polarity-management in disguise
- Pre-Mortem Analysis — when you want to anticipate failure forward instead of dismantling claims backward
/libertee:first-principles "your claim or belief"