Use this page for fast review before a strategy session, a design sprint, or any problem that deserves clear thinking. It covers all three pillars in compact form.
Pillar A — First-Principles and Systems Thinking
The Core Distinction
| Mode |
Method |
Output |
Best for |
| Reasoning by analogy |
Copy what worked before |
Incremental improvement |
Routine, low-stakes decisions |
| First-principles thinking |
Strip to bedrock facts; rebuild |
Genuinely new solutions |
High-stakes; broken templates |
Six First-Principles Tools
| Tool |
One-line description |
When to use |
| Socratic Questioning |
Ask layered questions about clarity, evidence, assumptions, implications |
Any strongly held belief you have not tested |
| 5 Whys |
Ask "Why?" five times in sequence to reach root cause |
Diagnosing a recurring problem |
| Feynman Technique |
Explain simply → find gaps → simplify again |
Checking whether you truly understand something |
| Decomposition |
Break a complex problem into independent components |
Before any analysis — map the parts first |
| Assumption surfacing |
List every belief you are treating as fact; label each fact/assumption |
Before committing to a strategy or design |
| Fact vs. assumption labelling |
Mark each claim: verified fact (F) or untested assumption (A) |
During any planning or diagnostic session |
8-Step First-Principles Checklist (10 minutes)
- Write the problem in one sentence.
- List everything you believe to be true about it.
- Label each item: F (verifiable fact) or A (assumption).
- Challenge every A: "What is the actual evidence?"
- Decompose: break into smallest independent sub-problems.
- Apply 5 Whys to the most important sub-problem.
- Rebuild from verified facts only — what solution does the bedrock actually support?
- Test your rebuilt solution against one real-world constraint before acting.
Systems Thinking: Core Vocabulary
| Term |
Plain meaning |
Classic example |
| Stock |
Quantity that accumulates / drains |
Water in a bathtub; customers on a waitlist |
| Flow |
Rate of change in a stock |
Monthly new signups (inflow); monthly churn (outflow) |
| Reinforcing loop |
Self-amplifying; snowball effect |
More users → more content → more users |
| Balancing loop |
Self-correcting; thermostat effect |
High price → fewer buyers → price drops |
| Delay |
Gap between action and effect |
Hiring takes 3 months; capacity appears later |
| Leverage point |
Small change → large, lasting effect |
Changing the goal of the system |
Meadows' Leverage Points (Weakest → Strongest)
WEAKEST ────────────────────────────────────── STRONGEST
│ │
Numbers → Feedback delays → Feedback structure │
→ Rules → Information flows → System goals │
→ Paradigm (shared beliefs that built the system) │
└──────────────────────────────────────────────────────────┘
Tweak a number = small effect.
Change the paradigm = everything changes.
Eight Essential Mental Models
- Second-order thinking — "and then what?" × 2
- Inversion — work backwards from failure
- Opportunity cost — every yes is a no to something else
- Circle of competence — know your edge; stay inside it
- Base rate / outside view — what usually happens before your special case
- Confirmation bias guard — actively seek disconfirming evidence
- Sunk cost flush — past investment is irrelevant to future decisions
- Latticework — apply multiple models simultaneously; no single lens is enough
Key takeaway: First-principles tools tell you what is actually true. Systems thinking tells you where to intervene. Mental models tell you what you are probably missing. Use all three before committing to a plan.
Pillar A — 20-Minute Quick Start
- Minutes 1–3: Write the problem in one sentence. List 10 beliefs about it.
- Minutes 4–8: Label each belief F or A. Challenge every A with "What is the actual evidence?"
- Minutes 9–13: Draw a quick causal loop diagram. Find the reinforcing loop driving the problem.
- Minutes 14–17: Apply 5 Whys to the highest-leverage node in your diagram.
- Minutes 18–20: State the one intervention that acts on the structure, not the symptom.
Pillar B — Habit and Behavior Design
Two Habit Loop Models Side by Side
| Stage |
Duhigg (3-part) |
Clear (4-part) |
Design lever |
| 1 |
Cue |
Cue |
Make it obvious |
| 2 |
— |
Craving |
Make it attractive |
| 3 |
Routine |
Response |
Make it easy |
| 4 |
Reward |
Reward |
Make it satisfying |
Four Laws of Behavior Change — and Their Inversions
| Law (build a habit) |
Inversion (break a habit) |
| Make it obvious — cue visible, habit stacked |
Make it invisible — remove the cue from the environment |
| Make it attractive — temptation bundling, social proof |
Make it unattractive — reframe the cost, not the desire |
| Make it easy — 2-minute rule, reduce friction to zero |
Make it hard — add friction, add steps, increase effort required |
| Make it satisfying — immediate reward, habit tracker |
Make it unsatisfying — accountability partner, public cost |
Behavior Design Models at a Glance
| Model |
Formula / structure |
Primary use |
| Fogg B = MAP |
Behavior = Motivation × Ability × Prompt (all must converge) |
Diagnosing why a behavior is not happening; raise Ability first |
| COM-B |
Capability + Opportunity + Motivation → Behavior |
Diagnosing the specific missing ingredient in behavior change |
| Hook Model (Eyal) |
Trigger → Action → Variable Reward → Investment |
Designing products that build automatic return behavior |
| Nudge / Choice Architecture |
Default + framing + friction + social norms |
Steering population-level behavior without removing choice |
Keystone Tactics
- Implementation intention: "I will [behavior] at [time] in [place]." — doubles follow-through.
- Habit stacking: "After I [existing habit], I will [new habit]."
- 2-Minute rule: Scale the new habit to under 2 minutes to start — always.
- Environment design: Put the cue where you cannot miss it; remove the competing cue.
- Temptation bundling: Pair a need-to-do with a want-to-do.
- Never miss twice: One missed day = accident. Two missed days = new bad habit. Show up anyway.
- Identity framing: "I am becoming a person who..." — tie habit to self-concept, not outcome.
Analogy: The Plateau of Latent Potential is like ice melting: nothing seems to happen between -20°C and -1°C, then everything changes at 0°C. Your habits are accumulating value below the surface long before results appear.
Ethics Guardrails for Product Behavior Design
| Check |
Pass condition |
Fail = dark pattern |
| Manipulation Matrix |
Improves user's life AND maker would use it |
Exploits user or maker would not use it themselves |
| Regret Test |
User would NOT regret the action next day |
User would regret with full information |
Common mistake: Designing for engagement instead of value. Variable rewards, streaks, and progress bars are neutral tools — they become dark patterns the moment the metric (time in app) diverges from the user's actual interest (outcome achieved).
Pillar B — 20-Minute Quick Start
- Minutes 1–3: Name one habit to build and one to break.
- Minutes 4–7: For the build habit — apply B=MAP: is motivation, ability, or prompt the missing piece?
- Minutes 8–11: Write the implementation intention. Identify the stacking anchor (existing habit it follows).
- Minutes 12–15: Scale it to 2 minutes. Design the environment change that makes the cue unavoidable.
- Minutes 16–18: Define the immediate reward (not the outcome — the feeling after completing it).
- Minutes 19–20: Write the identity statement: "I am becoming the kind of person who..."
Pillar C — Creativity and Idea Generation
Wallas's Four Stages of the Creative Process
┌─────────────┐ ┌─────────────┐ ┌─────────────┐ ┌─────────────┐
│ 1. │ │ 2. │ │ 3. │ │ 4. │
│ PREPARATION │→ │ INCUBATION │→ │ ILLUMINATION│→ │ VERIFICATION│
│ │ │ │ │ │ │ │
│ Load the │ │ Step away. │ │ The "aha" │ │ Test, refine│
│ problem │ │ DMN works. │ │ moment. │ │ and ship. │
│ deeply. │ │ Walk/sleep. │ │ Write it │ │ │
└─────────────┘ └─────────────┘ └─────────────┘ └─────────────┘
Note: Illumination only follows deep Preparation.
Skipping Preparation makes incubation empty.
Ten Idea-Generation Techniques
| Technique |
Core mechanism |
Best used when… |
| Brainstorming |
Rapid generation, judgment suspended |
Warm-up; diverse group; short session |
| Brainwriting (6-3-5) |
Written, anonymous, passed around |
Group has a loud voice or anchoring risk |
| SCAMPER |
Seven systematic mutations of an existing idea |
You have a starting concept to evolve |
| Lateral thinking / Po |
Deliberate logical jump; absurd provocation |
Stuck in a rut; obvious ideas exhausted |
| Six Thinking Hats |
Parallel modes (data/emotion/risk/optimism/creative/process) |
Group decision with competing agendas |
| Forced connections |
Random word / object → link to problem |
Need a completely unexpected angle |
| Analogical thinking / biomimicry |
Borrow solutions from distant domains or nature |
Engineering / design challenges with known natural analogues |
| How Might We (HMW) |
Reframe problem as open invitation |
Session opening; re-energizing a stuck group |
| First-principles decomposition |
Break to fundamentals; recombine freely |
Deep structural innovation; template is broken |
| Constraint-driven creativity |
Impose a tight limit to force novel solutions |
Too many options; need to break out of defaults |
SCAMPER Quick Reference
| Letter |
Prompt |
Example question |
| S | Substitute | What if we replaced [component] with something else? |
| C | Combine | What if we merged this with [another product/idea]? |
| A | Adapt | What has solved a similar problem in a different industry? |
| M | Modify / Magnify | What if we made it 10× larger / smaller / faster? |
| P | Put to other use | Who else could use this, or in what other context? |
| E | Eliminate | What can we remove without losing the core value? |
| R | Reverse / Rearrange | What if we did the opposite, or reversed the order? |
Divergent vs Convergent Thinking
|
Divergent |
Convergent |
| Goal |
Maximum quantity and variety of ideas |
Select the single best option |
| Rules |
No judgment; wild ideas welcome; build on others |
Evaluate rigorously; apply criteria; kill weak options |
| Timing |
First |
Second — never simultaneously |
| Tools |
Brainstorming, HMW, SCAMPER, lateral thinking |
Decision matrix, pre-mortem, second-order thinking |
Focused vs Diffuse Mode
FOCUSED MODE DIFFUSE MODE
───────────────── ─────────────────
Deep concentration Relaxed, wandering
Deliberate analysis Loose associations
Sequential logic Cross-domain jumps
Best for: working through Best for: incubation,
known problem steps "aha" moments, novel
connections
Switch by: taking a walk,
napping, showering, exercising
Best practice: Schedule creative work in two blocks: a focused session (deep preparation, analysis, drafting) followed by a deliberate break (walk, exercise, unrelated task), then return to capture the insights that emerged. This cycles both modes and reliably outperforms grinding through in one marathon session.
Creativity Killers to Avoid
- Evaluating while generating — kills divergence before it produces enough raw material.
- Waiting for the "right" idea before starting — quantity precedes quality; begin output immediately.
- Skipping preparation and expecting incubation to work — the DMN needs material to process.
- Working in a single domain — combinational creativity requires diverse inputs.
- Treating creative block as failure — it is a signal to switch to diffuse mode, not to try harder.
Pillar C — 20-Minute Idea Session Template
- Minutes 1–2: Write a "How Might We" reframe of the problem. (Not "how do we fix X" — "how might we help [user] achieve [goal] despite [constraint]?")
- Minutes 3–8: Pure divergent generation — no judgment. Aim for 15+ ideas minimum. Use SCAMPER prompts if stuck.
- Minutes 9–11: Forced connections round — pick a random word or object; generate 3–5 more ideas by linking it to the problem.
- Minutes 12–14: Take a short break — stand up, walk, look away from the screen.
- Minutes 15–18: Convergent phase — review all ideas; mark the three most promising; identify the one constraint that would make each viable.
- Minutes 19–20: Write a one-sentence next action for the top idea. Capture all others in your capture system.
The Thinking Operating System — One-Page Summary
┌──────────────────────────────────────────────────────────────┐
│ STAGE 1: UNDERSTAND THE REAL PROBLEM │
│ Tools: 5 Whys · Decomposition · Assumption labelling │
│ Output: Verified bedrock facts; root cause identified │
├──────────────────────────────────────────────────────────────┤
│ STAGE 2: GENERATE MANY SOLUTIONS │
│ Tools: HMW · SCAMPER · Brainstorming · Forced connections │
│ Output: 15+ options; wild ideas included; no judgment yet │
├──────────────────────────────────────────────────────────────┤
│ STAGE 3: EVALUATE RIGOROUSLY │
│ Tools: Second-order thinking · Inversion · Pre-mortem │
│ · Latticework of mental models │
│ Output: One chosen path; risks surfaced and mitigated │
├──────────────────────────────────────────────────────────────┤
│ STAGE 4: SHIP THE BEHAVIOR │
│ Tools: 4 Laws of Behavior Change · Implementation intention │
│ · Habit stacking · B=MAP friction audit │
│ Output: Durable action that holds after motivation fades │
└──────────────────────────────────────────────────────────────┘
Key takeaway: The four stages are a chain, not a menu. Skipping Stage 1 means you may solve the wrong problem brilliantly. Skipping Stage 2 means you pick from too few options. Skipping Stage 3 means you ship the first idea that feels good. Skipping Stage 4 means the insight dies in a notebook. Run all four, every time.