first-principles-thinking

name	first-principles-thinking
description	Use when assumptions, analogies, legacy constraints, or accepted ways of working may be hiding a better solution. Use when applying First Principles Thinking, reasoning from fundamentals, assumption stripping, rebuilding from basic truths, or non-incremental problem solving.
license	Apache-2.0

First Principles Thinking

Use this skill to run First Principles Thinking as a practical consulting method, not as a generic inspiration quote.

Method Notes

• First principles thinking breaks a problem into the most basic truths that are still reliable in the current context.
• It deliberately avoids solving only by analogy, precedent, habit, or "how this is usually done."
• A useful first principle is not necessarily a universal law; it can be a context-specific truth that cannot be reduced further for the decision at hand.
• The method should rebuild options from the ground up, then reconnect them to constraints, economics, and execution reality.

Required Inputs

Collect or infer these inputs before execution:

• problem statement
• current assumptions
• known constraints
• evidence or facts
• desired outcome

If an input is missing, do not block automatically. Mark it as missing, state the assumption used, and add a validation action.

When Not To Use

Do not use for a routine root-cause investigation, evidence classification, or option scoring. Use five-whys-root-cause for one cause chain, fishbone-diagram for multi-factor operational causes, and evidence-map when the fact base is not yet reliable. Use first principles when inherited assumptions or analogy constrain the option set.

Step-by-Step Execution

Step	Required input	How to execute	Output
State the problem plainly	Problem statement, desired outcome, decision context.	Rewrite the issue without inherited labels, solution language, or organizational shorthand.	Plain problem statement.
List assumptions and analogies	Current beliefs, constraints, common practice, benchmark logic.	Separate facts from assumptions, habits, analogies, and rules of thumb.	Assumption inventory.
Strip to fundamentals	Evidence, physical/economic/customer/process realities.	Ask what must be true, what is directly observed, and what cannot be reduced further for this decision.	First-principles breakdown.
Rebuild options	Fundamental truths, desired outcome, constraints.	Create options from the fundamentals instead of starting from existing solutions.	Rebuilt solution options.
Test against reality	Options, constraints, economics, stakeholder needs, validation data.	Check feasibility, risks, tradeoffs, and the fastest test that would prove or disprove each option.	Validation plan and recommended option.

Output Template

### 1. Problem Frame
- Plain problem statement:
- Desired outcome:
- Decision boundary:

### 2. Assumption Inventory
| Assumption / analogy | Type | Evidence | Keep / challenge / test |
|---|---|---|---|
|  | fact / assumption / analogy / constraint |  |  |

### 3. First Principles
- Fundamental truth 1:
- Fundamental truth 2:
- Fundamental truth 3:

### 4. Rebuilt Options
| Option | Built from which first principle | Why it may work | Main risk | Fastest test |
|---|---|---|---|---|
|  |  |  |  |  |

### 5. Recommendation
- Best next move:
- What to stop assuming:
- Validation signal:

Quality Gate

• Do not confuse first principles with personal opinion.
• Every first principle must be backed by evidence, direct observation, economics, physics, customer reality, process reality, or a clearly stated context boundary.
• The final options must be meaningfully different from the inherited solution set.
• Do not ignore execution constraints; reintroduce constraints after rebuilding options from fundamentals.
• Keep wording professional and plain enough that a smart non-specialist can use it without translation.