mcltyl First-Principles Thinking Skill
Definition
Break down problems to their most basic facts, then re-derive solutions from there — rather than relying on analogies, conventions, or "that's how everyone does it."
Core question: "What is the fundamental truth about this? Starting from that truth, what can I derive?"
When to Activate
Activation conditions (any one triggers):
- Existing approaches may be wrong, but no one has questioned them
- The problem is new with no good precedents
- High-stakes decision worth deep analysis
- User is stuck between contradictory advice
- Need to understand "why it works" not just "does it work"
Do not activate when:
- Problem has a clear standard answer (just look it up)
- Routine operations with proven processes
- Extreme time pressure requiring immediate action
Knowing when NOT to use it is part of first-principles thinking.
Analysis Process
Step 1: Identify the Purpose
Ask: "What is this ultimately trying to achieve?"
Not "what am I being asked to do" but "what outcome is this action meant to produce." If the purpose itself is flawed, all subsequent analysis is meaningless.
Step 2: Break Down to Basic Facts
Ask: "What do I know for certain to be true about this?"
Rules:
- Accept only verifiable facts, not assumptions, conventions, or "usually"
- Distinguish "facts" from "interpretations of facts"
- Distinguish "causation" from "correlation"
Step 3: Identify Hidden Assumptions
Ask: "What unexamined assumptions am I accepting?"
Common hidden assumptions:
- "This has always been done this way" (convention ≠ optimal)
- "Everyone says so" (consensus ≠ fact)
- "It worked last time so it will work again" (history ≠ future)
- "This is too complex to change" (complex ≠ immutable)
Step 4: Re-derive from Basic Facts
Ask: "Given only these facts, uninfluenced by existing solutions, what would I do?"
Build a solution from scratch, then compare with existing approaches. The differences are where deeper examination is needed.
Step 5: Validate the Derivation
Ask: "Which step in my reasoning is weakest? If that step is wrong, what happens to my conclusion?"
- Find the weakest link in the reasoning chain
- Test: if that link reverses, does the conclusion still hold?
- If not, that's where more information or careful judgment is needed
Common Pitfalls
| Pitfall | Symptom | Solution |
|---|---|---|
| Fake first principles | Treating "industry wisdom" as basic facts | Ask one more layer: "Where did this come from?" |
| Analysis paralysis | Endless decomposition, never deciding | Set a depth limit; decide with best available info |
| Ignoring practicality | Deriving theoretical optima that can't be executed | Include "feasibility" as a basic fact |
| Dogmatism | Using only your own reasoning, ignoring others' experience | First principles doesn't reject experience; it rejects unexamined experience |
Combining with Other Skills
This skill is a foundational methodology. Combine with other skills as follows:
- First, use first principles to clarify the problem's essence (What is this really trying to solve?)
- Then, use domain skills for specialized frameworks (What proven methods exist in that domain?)
- Finally, use first principles to validate conclusions (Does every step of this solution hold up?)
Response Principles
- Don't pretend things are simple — if genuinely complex, explain where the complexity lies
- Distinguish known from unknown — clearly mark "this is fact" vs "this is my inference"
- Show the reasoning process, not just conclusions — let users verify each step
- Challenge users' hidden assumptions, but through questions rather than assertions