Obscure methods and mental models that change how you think about thinking. Each one a tool most people never discover.

The Zettelkasten Method

Note-taking system that builds a “second brain.”

The origin: German sociologist Niklas Luhmann used it to write:

  • 70 books
  • 400+ academic articles
  • In 40 years

He said his productivity came from his Zettelkasten (slip-box).

How it works:

  1. Fleeting notes: Capture ideas immediately
  2. Literature notes: Summarize what you read (in your own words)
  3. Permanent notes: One idea per note, written clearly
  4. Link notes: Connect related ideas
  5. Index: Entry points to chains of thought

The magic: Your notes become a thinking partner.

Writing one note leads to another. Ideas connect. Insights emerge from connections.

Not a filing system. A thinking system.

Modern tools:

  • Obsidian
  • Roam Research
  • Logseq

The shift: From storing information → Developing thoughts

Your past notes inform current thinking.

Luhmann: “I never force myself to do anything I don’t feel like. When I’m stuck, I switch to another note.”

His second brain did the heavy lifting.


Oblique Strategies

Brian Eno’s creative unblocking cards.

What they are: Deck of cards with cryptic prompts:

  • “What would your closest friend do?”
  • “Use an old idea”
  • “Honor thy error as a hidden intention”
  • “Remove specifics and convert to ambiguities”

When you’re stuck: Draw a card. Apply the constraint.

Why it works: Creative blocks come from mental ruts.

Random constraints force new neural pathways.

Example: Stuck on a design. Card says: “What would your closest friend do?” Shifts perspective. Solution appears.

The principle: You can’t solve problems from the same thinking that created them.

Oblique = Indirect

Frontal assault fails. Sideways approach works.

You can buy the physical deck or use online versions.

Randomness is the feature, not a bug.


The OODA Loop

Military decision-making framework: Observe, Orient, Decide, Act

Developed by: Fighter pilot John Boyd

The loop:

  1. Observe: Gather information
  2. Orient: Analyze and synthesize
  3. Decide: Choose action
  4. Act: Execute
  5. Repeat

The insight: Speed of iteration beats perfect decisions.

In combat: Faster OODA loop = You’re inside opponent’s decision cycle = You win

In life: Don’t aim for perfect decisions.

Aim for fast cycles:

  • Small experiments
  • Quick feedback
  • Rapid iteration
  • Continuous adjustment

Startup version: Build → Measure → Learn → Repeat

The mistake: Spending forever in “Orient” trying to get it perfect.

Boyd’s lesson: Action generates information.

The loop requires action to continue.

Paralysis by analysis vs. OODA loop velocity

Move fast. Learn faster.


Second-Order Thinking

Considering consequences of consequences.

First-order: Immediate effect Second-order: Effect of the effect Third-order: And so on…

Example:

Problem: Traffic congestion

First-order solution: Build more roads Second-order consequence: More roads → More people drive → More congestion (induced demand)

Example 2:

Action: Get promoted

First-order: More money, status Second-order: More responsibility, less free time, higher stress, relationship strain Third-order: Health issues, divorce, burnout

Most people stop at first-order.

Smart people think second-order.

Chess-like life strategy: Don’t ask: “What happens if I do this?”

Ask: “Then what? And then what? And then what?”

The practice: For any decision, ask:

  • What happens immediately?
  • What happens after that?
  • What happens after that?
  • Who responds to my action?
  • How do they respond to the response?

Unintended consequences aren’t unforeseeable.

They’re just second-order.


Inversion

Solving problems backwards.

Instead of: “How do I succeed?”

Ask: “How would I guarantee failure? Now avoid that.”

Charlie Munger’s approach: “Invert, always invert.”

Examples:

Question: How to have a good marriage?

Inversion: How to destroy a marriage?

  • Never communicate
  • Keep score
  • Prioritize work over partner
  • Stop dating
  • Let resentment build

Now avoid those things.

Question: How to build a successful business?

Inversion: How to guarantee business failure?

  • Ignore customers
  • Burn cash
  • Hire badly
  • No product-market fit
  • Never iterate

Now avoid those things.

Why it works: Easier to identify what kills something than what makes it thrive.

Avoiding stupidity is easier than achieving brilliance.

The shift: From “What should I do?” → “What must I not do?”

Failure is easier to predict than success.

Use that.


The Barbell Strategy

Extreme risk management from Nassim Taleb.

The strategy:

  • 90% extremely safe
  • 10% extremely risky
  • Nothing in the middle

Examples:

Investing:

  • 90% treasury bonds
  • 10% high-risk startups/crypto
  • 0% “moderate” stocks

Career:

  • Stable job + wild side projects
  • Not: Medium-risk corporate ladder

Learning:

  • Deep fundamentals + experimental cutting-edge
  • Not: Following trendy frameworks

Why it works: The middle is deceptively risky.

“Moderate” investments:

  • Can still lose everything
  • But with limited upside

Barbell:

  • Safe side protects you from ruin
  • Risky side gives unlimited upside
  • Asymmetric payoff

You can’t lose more than 10%. But you can gain unlimited.

The principle: Eliminate fragility (90% safe) while retaining antifragility (10% risky).

Most people do the opposite: 100% in the “moderate” middle.

Which means:

  • Moderate risk
  • Moderate reward
  • Vulnerable to black swans

Barbell = Extreme safety + Extreme opportunity


Optionality

Keeping options open has value itself.

The concept: Some decisions open more doors. Some decisions close doors.

High optionality: Opens future choices Low optionality: Closes future choices

Examples:

High optionality:

  • Learning to code (applies to many careers)
  • Living in a major city (more opportunities)
  • Freelancing (multiple clients, not dependent on one)
  • Renting (can move easily)

Low optionality:

  • Specializing in dying technology
  • Living in one-industry town
  • Single employer dependency
  • Buying house in declining area

The mistake: Optimizing current situation while destroying future options.

Example: High-paying job in dying industry = Short-term win, long-term risk

Taleb’s principle: Value optionality over efficiency.

Slightly less optimal now + more options later > Perfect now + trapped

The practice: Before deciding, ask:

  • “Does this open or close future doors?”
  • “Am I trading optionality for efficiency?”
  • “What if I’m wrong?”

Life isn’t chess where you know all the rules.

It’s poker where new cards keep appearing.

Keep options open.


Deliberate Practice vs. Naive Practice

Why 10,000 hours don’t automatically make you expert.

Naive practice:

  • Repetition without feedback
  • Comfort zone
  • Autopilot
  • No specific goals

Result: Plateau despite years of experience

Deliberate practice:

  • Specific goals
  • Immediate feedback
  • Uncomfortable (stretching)
  • Full attention
  • Expert guidance

Result: Continuous improvement

Examples:

Naive: Play guitar casually for 10 years → Still mediocre

Deliberate: Practice specific techniques, get coaching, record yourself, push boundaries → Expert in 2 years

Why most people plateau: They repeat what they already know.

Deliberate practice: Focuses on weaknesses.

The discomfort test: If it’s comfortable, it’s naive practice.

If it’s uncomfortable, it’s deliberate.

You can’t coast to expertise.

10,000 hours of comfort = 10,000 hours of mediocrity

1,000 hours of deliberate discomfort = Mastery

Time doesn’t create skill. Discomfort does.


The Map Is Not the Territory

All models are wrong. Some are useful.

The concept: Your mental model of reality ≠ Reality

Examples:

Map: Represents terrain Territory: Actual terrain Mistake: Treating map as terrain

Business plan: Model of business Actual business: Messy reality Mistake: Following plan when reality changed

Your beliefs about someone: Model The actual person: Territory Mistake: Thinking you know them completely

The principle: Models simplify. Reality is complex.

Models are tools, not truth.

When it matters:

Good: “This model helps me navigate” Bad: “This model is reality”

Dogma = Confusing map with territory

The practice: Hold models lightly.

“This is my current understanding” not “This is how it is”

Update maps when territory changes.

Reality doesn’t care about your model.


The Focusing Illusion

“Nothing is as important as you think it is while you’re thinking about it.” - Daniel Kahneman

The pattern: Whatever you focus on dominates your perception.

Examples:

Thinking about salary: Feels like everything

Later: Other factors matter more (colleagues, commute, meaning)

Thinking about new car: Feels life-changing

After buying: Returns to background, life unchanged

Planning vacation: Feels crucial

During vacation: Nice, but not as meaningful as imagined

The illusion: Your attention magnifies importance.

Why it matters: You misjudge what will actually matter.

The research: People overestimate impact of:

  • Salary increases
  • Possessions
  • Status
  • Living location

On happiness and life satisfaction.

The fix: When obsessing over something, ask: “Am I experiencing the focusing illusion?”

Perspective comes from looking away.

Step back. Consider broader context.

The thing consuming your attention isn’t as important as it feels right now.


Shinrin-Yoku (Forest Bathing)

Japanese practice: Mindful presence in forests.

Not hiking. Not exercising.

Just being present in nature.

The practice:

  • Walk slowly through forest
  • No phone, no podcast
  • Engage senses (sight, smell, sound, touch)
  • No destination
  • 2-4 hours

The science: Measurable effects:

  • Reduced cortisol (stress hormone)
  • Lower blood pressure
  • Improved immune function
  • Better mood
  • Increased creativity

Why it works: Attention restoration theory:

Modern life = Directed attention (effortful) Nature = Involuntary attention (effortless)

Forests restore depleted attention.

The shift: From nature as exercise venue → Nature as therapy

You don’t have to do anything.

Just be there.

Modern humans are nature-deprived.

Forest bathing is the antidote.


The Lindy Effect

Things that have lasted a long time will likely last longer.

The pattern: Future life expectancy is proportional to current age.

Examples:

Book 400 years old: Likely to last another 400 years

Book 2 years old: Might be forgotten in 2 years

Ancient philosophy (2,000+ years): Will outlast modern self-help

Startup (6 months old): Unlikely to last 10 years

Why it works: Time is a quality filter.

Bad ideas die. Good ideas survive.

The longer something survives, the more proven its resilience.

Application:

Learning: Study old books before new trends

Investment: Trust established companies/ideas

Advice: Ancient wisdom > Modern hacks

Technology: Older tech often more reliable

The counterintuitive part: The future belongs to the old, not the new.

Most new things die quickly.

What survives becomes antifragile.

Time reveals quality.


Key Patterns

These systems share a structure: Meta-level thinking

The lessons:

  1. Zettelkasten: Thinking system, not storage
  2. Oblique Strategies: Sideways beats frontal
  3. OODA Loop: Speed beats perfection
  4. Second-order: Think consequences of consequences
  5. Inversion: Avoid stupidity beats seeking brilliance
  6. Barbell: Extremes beat middle
  7. Optionality: Keep doors open
  8. Deliberate practice: Discomfort creates skill
  9. Map/Territory: Models are tools, not truth
  10. Focusing Illusion: Attention magnifies importance
  11. Forest Bathing: Nature restores attention
  12. Lindy Effect: Time reveals quality

The meta-insight:

Most people operate at object level (the thing itself).

These methods operate at meta level (thinking about thinking).

You can’t solve problems at the level they were created.

You need frameworks that operate one level up.

These aren’t life hacks.

They’re cognitive infrastructure.

The scaffolding that lets you think better about everything else.

You don’t need all of them.

But knowing they exist changes what’s possible.

Most limitations aren’t in reality.

They’re in how you think about reality.

Change the lens. Change what you see.

That’s what these systems do.