# First-Principles Thinking

Reference guideline for Wing-1 deep-thinking work — strip away
assumptions and conventions to reach fundamental truths, then rebuild
understanding from the ground up. Distinct from `inversion-thinking`
(which negates the goal) — first principles **dissolve** the goal into
verified primitives and reconstruct it without inherited convention.
Adopted under the **Reference-Guideline Sunset Policy** and
cross-referenced from:

- [`deep-reading-analyst`](../../../.agent-src.uncondensed/skills/deep-reading-analyst/SKILL.md)
  — L3 Deep analysis depth.
- [`mental-models`](mental-models.md) — Munger's lattice; first
  principles is the foundational physics-style lens.
- [`improve-before-implement`](../../../.agent-src.uncondensed/rules/improve-before-implement.md)
  — challenge the framing of a request before coding it.
- [`inversion-thinking`](inversion-thinking.md) — pair: first
  principles rebuilds; inversion stress-tests the rebuild.

> **Core principle:** "What is definitely, provably true?" — strip
> the inherited and rebuild from primitives.

## Three-Step Process

### Step 1: Identify assumptions

**Ask:** *"What do we assume to be true about this?"*

List all implicit and explicit assumptions in the content:

- Unstated premises.
- Inherited wisdom (*"everyone knows…"*).
- Industry conventions.
- Historical precedents treated as universal laws.

**Example from business:**

- Assumption: *"We need a physical store to sell products."*
- Question: is this fundamentally true or historically convenient?

### Step 2: Break down to fundamentals

**Ask:** *"What is definitely, provably true?"*

Reduce to indisputable facts:

- Physical laws (if applicable).
- Mathematical truths.
- Core human needs / behaviors.
- Cause-effect relationships you can verify.

**Sorting Framework:**

```
Claim → Ask: "How do I know this is true?"
    ↓
├─ "It just is"                       → Probably an assumption, dig deeper
├─ "That's how it's always done"      → Convention, not fundamental
├─ "X happens, then Y happens"        → Potential fundamental (verify causation)
└─ "Mathematically/physically must be true" → Fundamental
```

### Step 3: Rebuild from scratch

**Ask:** *"Starting from fundamentals only, what logically follows?"*

Reconstruct without importing old assumptions:

1. Begin with verified fundamentals.
2. Each step must logically follow from previous.
3. Note where you make new assumptions (be explicit).
4. Compare new construction to original concept.

## Application Template

```markdown
## Original Concept / Argument
[What the author claims]

## Hidden Assumptions
- Assumption 1: [Something taken as given]
- Assumption 2: [...]

## Verified Fundamentals
- Fundamental 1: [Provably true core fact]
- Fundamental 2: [...]

## Rebuilt Understanding
Starting from fundamentals only:
Step 1: [First logical derivation]
Step 2: [Second logical derivation]
...
Conclusion: [What actually follows]

## Comparison
Original vs. rebuilt:
- What survived: [Fundamentally sound ideas]
- What doesn't hold: [Based on questionable assumptions]
- New insights: [What rebuilding revealed]
```


## Common First Principles by Domain

### Business / economics

- People act in self-interest (with caveats).
- Supply and demand affect price.
- Value = willingness to pay.
- Scarcity creates value.

### Psychology / human behavior

- Humans seek pleasure, avoid pain.
- Social status matters to humans.
- Cognitive biases exist (not "people are rational").
- Habits form through repetition.

### Technology

- Information can be copied at near-zero cost.
- Network effects: value ∝ n² (Metcalfe's law).
- Moore's law (transistor density doubles ~every 2 years).
- Computation has energy cost.

### Physics / reality

- Energy is conserved.
- Entropy increases.
- Speed of light is constant.
- Cause precedes effect.

## Red Flags: Pseudo-First-Principles

Watch for claims disguised as fundamentals:

- *"People always prefer X"* (overgeneralization).
- *"This is just human nature"* (often cultural).
- *"Economics proves…"* (many schools of economics).
- *"Science says…"* (which study? replicated?).

**Test:** can you point to specific evidence / mechanism, or is it
folk wisdom?

## Powerful Questions

- *"Why is this true?"* (repeat 5 times — "5 Whys").
- *"What must be true for this to work?"*
- *"If I couldn't do it this way, what's another path?"*
- *"What would an alien with no context think?"*
- *"What if the opposite were true?"*

## Worked Example — *"Need for College Education"*

**Assumptions:**

- Need degree to get good job.
- Learning requires formal institution.
- 18–22 is the right age.
- Four years is optimal duration.

**Fundamentals:**

- Employers want skilled workers.
- Skills can be demonstrated.
- Learning requires time + practice.
- Knowledge can be transmitted.

**Rebuilt:**

- → Employers want proof of skill.
- → Proof can be: degree OR portfolio OR test OR track record.
- → Therefore, degree is one option, not necessity.
- → Insight: focus on skill + proof, not credential alone.

## Practical Use in Reading

When analyzing content:

1. **Identify claims** that seem absolute.
2. **Challenge foundations:** *"Does this HAVE to be true?"*
3. **Verify causation:** *"Does A truly cause B, or just correlate?"*
4. **Rebuild the argument** from indisputable facts only.
5. **Compare** what survives vs. what was assumption.

This exposes weak arguments and strengthens valid ones.

---

## ADOPT citation

Adopted from [`ginobefun/deep-reading-analyst-skill`](https://github.com/ginobefun/deep-reading-analyst-skill) @ commit `26cd7dc9` · `src/deep-reading-analyst/references/first_principles.md` · MIT License.
