Mental Models

A growing library of the most powerful thinking frameworks — explained visually, with real examples and practical steps.

Inversion

Instead of asking how to succeed, ask what would guarantee failure — then avoid it.

Foundation General ThinkingMathematics

First Principles Thinking

Break any problem down to its fundamental truths, then build your reasoning up from there.

Foundation General ThinkingPhysics

Second-Order Thinking

Consider not just the immediate consequences of a decision, but the consequences of those consequences.

Foundation General ThinkingSystems Thinking

Circle of Competence

Know what you know, know what you don't know, and stay honest about the boundary.

Foundation General ThinkingPsychology

The Map Is Not the Territory

Every model of reality is a simplification. Don't confuse your map with the actual terrain.

Foundation General ThinkingPhilosophy

Pre-Mortem

Before starting, imagine the project has already failed. Then figure out why.

Foundation General ThinkingPsychology

Occam's Razor

The simplest explanation that fits the evidence is usually the correct one.

Foundation General ThinkingPhilosophy

Hanlon's Razor

Never attribute to malice that which can be adequately explained by ignorance, incompetence, or neglect.

Foundation PsychologyCommunication

Probabilistic Thinking

Think in likelihoods, not certainties. Assign probabilities to outcomes instead of assuming binary results.

Intermediate MathematicsGeneral Thinking

Feedback Loops

Every system has outputs that feed back into inputs — reinforcing or balancing the system's behaviour over time.

Intermediate Systems Thinking

Margin of Safety

Build a buffer between what you expect and what you plan for. The world will surprise you.

Foundation General ThinkingEngineering

Opportunity Cost

The true cost of anything is whatever you give up to get it — including the next best alternative.

Foundation EconomicsGeneral Thinking

Antifragility

Some things don't just survive shocks — they get stronger from them. Position yourself to benefit from disorder.

Intermediate Systems ThinkingEconomics

Thought Experiments

Test ideas by running them in your imagination rather than in the real world — cheaper, faster, and sometimes just as revealing.

Intermediate General ThinkingPhysics

Eisenhower Matrix

Separate what's urgent from what's important. Most people spend their lives on the wrong quadrant.

Foundation General Thinking

Bayesian Updating

Start with your best guess, then update it proportionally as new evidence arrives.

Intermediate MathematicsPsychology

Confirmation Bias

We instinctively seek out information that confirms what we already believe — and ignore what contradicts it.

Foundation Psychology

Dunning-Kruger Effect

People with low competence in a domain tend to overestimate their ability, while experts tend to underestimate theirs.

Foundation Psychology

Loss Aversion

Losses hurt roughly twice as much as equivalent gains feel good — and this asymmetry distorts nearly every decision you make.

Intermediate PsychologyEconomics

Incentives

Never ask why someone is behaving a certain way until you understand what they're incentivised to do.

Foundation EconomicsPsychology

Comparative Advantage

Do what you're relatively best at, even if someone else is absolutely better at everything.

Intermediate Economics

Supply and Demand

The price and availability of anything — goods, jobs, attention, ideas — is shaped by how much exists relative to how much is wanted.

Foundation Economics

Leverage Points

In any system, there are specific places where a small change produces disproportionately large effects.

Intermediate Systems Thinking

Emergence

Complex behaviour arises from simple rules followed by many agents — the whole is genuinely different from the sum of its parts.

Intermediate Systems ThinkingBiology

Natural Selection

What works survives; what doesn't, disappears. This principle applies far beyond biology — to ideas, businesses, and habits.

Intermediate Biology

Red Queen Effect

You have to keep running just to stay in place — because everyone else is running too.

Intermediate BiologyEconomics

Critical Mass

Some processes need a minimum threshold of input before anything happens — then they suddenly accelerate.

Intermediate PhysicsSystems Thinking

Entropy

Everything tends toward disorder unless energy is applied to maintain order. This is true for systems, relationships, and organisations.

Intermediate Physics

Steelmanning

Before arguing against a position, make it as strong as possible. Defeat the best version of an argument, not the weakest.

Foundation CommunicationPhilosophy

Reciprocity

People feel compelled to return favours, match concessions, and treat you the way you treat them.

Foundation PsychologyCommunication

Regret Minimisation

Project yourself to age 80 and ask which choice you'll regret not making. That's usually the right one.

Foundation General Thinking

Marginal Thinking

Don't evaluate the total — evaluate the next unit. The value of one more hour, one more dollar, one more feature is what matters.

Intermediate EconomicsGeneral Thinking

Pareto Principle

Roughly 80% of effects come from 20% of causes. Find the vital few and ignore the trivial many.

Foundation General ThinkingMathematics

Survivorship Bias

We study the winners and forget the losers — which distorts our understanding of what actually causes success.

Foundation PsychologyMathematics

Sunk Cost Fallacy

Money, time, or effort already spent should not influence future decisions — but it almost always does.

Foundation EconomicsPsychology

Thinking in Bets

Separate decision quality from outcome quality. A good decision can have a bad outcome, and vice versa.

Intermediate PsychologyMathematics

Via Negativa

Improve by removing what's harmful rather than adding what might help. Subtraction often beats addition.

Intermediate General ThinkingPhilosophy

Anchoring

The first piece of information you encounter disproportionately shapes all subsequent judgments.

Foundation Psychology

Availability Heuristic

We judge the likelihood of events by how easily examples come to mind — not by actual frequency.

Foundation Psychology

Framing Effect

The same information presented differently leads to different decisions — even when the underlying facts are identical.

Intermediate Psychology

Goodhart's Law

When a measure becomes a target, it ceases to be a good measure.

Intermediate Systems Thinking

Compounding

Small consistent gains accumulate into extraordinary results over time — in finance, skills, relationships, and knowledge.

Foundation Mathematics

Normal Distribution

Most outcomes cluster around the average, with extreme outcomes being rare — except when they are not.

Intermediate Mathematics

Asymmetric Risk

Seek decisions where the potential upside vastly outweighs the potential downside — even if success is unlikely.

Intermediate Economics

Narrative Fallacy

Humans compulsively construct stories to explain random events, creating false causation and illusory patterns.

Intermediate Psychology

Circle of Control

Focus your energy on what you can control, accept what you cannot, and learn to tell the difference.

Foundation General Thinking

Local vs Global Optima

The best option within your current constraints may not be the best option overall — sometimes you need to get worse before you can get better.

Intermediate Mathematics

Chesterton's Fence

Before removing something, understand why it was put there in the first place.

Foundation General Thinking

Cobra Effect

Well-intentioned interventions often produce the opposite of their intended effect when people respond strategically to new incentives.

Intermediate Systems Thinking
⊕10

10x Thinking

Instead of asking how to improve by 10%, ask how to improve by 10x. The radical question forces you to abandon incremental approaches and find breakthrough solutions.

Intermediate General ThinkingEngineering

Abstraction

Hide complexity behind simple interfaces. You don't need to understand how an engine works to drive a car.

Intermediate EngineeringGeneral Thinking
⌬⌬

Accidental vs Essential Complexity

Some complexity is inherent to the problem. Some is created by the solution. Learning to tell the difference is a superpower.

Intermediate EngineeringSystems Thinking

Accountability

People who bear consequences make better decisions. Design systems where decision-makers face the results of their choices.

Foundation General ThinkingEconomics
⊏⊏

Adverse Selection

When one side of a market has more information, the people most likely to participate are those who benefit most — often at the other side's expense.

Intermediate Economics

Affect Heuristic

We make judgments based on current emotions rather than objective analysis — if something feels scary, we overestimate its risk.

Intermediate Psychology

Anchoring and Adjustment

We start from an initial value (the anchor) and adjust insufficiently from it — our final estimate stays too close to the starting point.

Foundation PsychologyMathematics

Asymmetric Information

One party in a transaction knows more than the other. This imbalance drives much of economic behaviour.

Intermediate Economics
⟫⟫

Bandwagon Effect

The tendency to adopt beliefs and behaviours simply because many other people do.

Foundation Psychology

Barbell Strategy

Combine extreme safety with small, high-upside bets. Avoid the dangerous middle.

Intermediate EconomicsGeneral Thinking

Base Rate Neglect

We ignore how common or rare something is in general, and focus too much on the specific case in front of us.

Intermediate MathematicsPsychology
P

Base Rates and Priors

Before evaluating specific evidence, check how common the thing is in general. The base rate is your starting point.

Intermediate Mathematics

Bottleneck / Theory of Constraints

Every system has one constraint that limits overall throughput. Improving anything else is waste until you fix the bottleneck.

Intermediate Systems ThinkingEngineering
⊕⊙

Building a Second Brain

Offload information from your biological memory to an external system so your brain can focus on thinking, not remembering.

Foundation General Thinking
🦋

Butterfly Effect

In complex systems, tiny changes in initial conditions can produce vastly different outcomes.

Intermediate Systems ThinkingMathematics

Chesterton's Fence (Revisited)

Before removing something that seems useless, understand why it was put there. It may serve a purpose you haven't noticed.

Foundation General ThinkingPhilosophy
◎◎

Circle of Influence

Focus energy on what you can control, not what you can't. Most worry is spent on the wrong circle.

Foundation PsychologyGeneral Thinking

Clustering Illusion

We see patterns in random data — streaks, clusters, and trends that are actually just statistical noise.

Intermediate PsychologyMathematics

Complexity Bias

We tend to prefer complex explanations and solutions over simple ones, even when the simple version works better.

Foundation PsychologyGeneral Thinking
≠→

Correlation vs Causation

Two things happening together doesn't mean one causes the other. Ice cream sales and drowning rates both rise in summer — but ice cream doesn't cause drowning.

Foundation General ThinkingMathematics

Counterfactual Thinking

Ask 'what if things had been different?' to separate skill from luck and find the real causes.

Intermediate General ThinkingPhilosophy

Creative Destruction

Economic progress requires old industries and methods to be destroyed by new ones. The process is painful but essential for growth.

Intermediate EconomicsSystems Thinking

Curse of Knowledge

Once you know something, you can't imagine not knowing it — making it hard to explain to someone who doesn't know it yet.

Foundation PsychologyCommunication
◈◈

Decoy Effect

Adding a clearly inferior option makes one of the other options look more attractive by comparison.

Intermediate PsychologyEconomics

Devil's Advocate

Deliberately argue the opposing side to stress-test your own position.

Foundation General ThinkingCommunication

Diminishing Returns

Each additional unit of input produces less additional output. The first hour of practice helps more than the hundredth.

Foundation EconomicsGeneral Thinking

Disagree and Commit

When consensus can't be reached and the decision is reversible, it's better to commit to one direction and learn from results than to debate indefinitely.

Foundation General ThinkingCommunication
⊟⊟

Distinction Bias

When comparing options side by side, we notice differences that wouldn't matter in actual use. The comparison mode distorts our evaluation.

Intermediate Psychology
⊕⊕

Domain Dependence

People often fail to transfer knowledge from one domain to another, even when the underlying principle is identical.

Intermediate PsychologyGeneral Thinking
⊞⊞⊞

Dunbar's Number

Humans can maintain meaningful relationships with roughly 150 people. Beyond that, social cohesion requires formal structures.

Intermediate PsychologyBiology
⊕⊕⊕⊕

Endowment Effect

We value things more once we own them — simply possessing something increases its perceived worth.

Foundation PsychologyEconomics

Ergodicity

The average outcome for a group can be completely different from the typical outcome for an individual over time.

Advanced MathematicsEconomics
Σ

Expected Value

Multiply each possible outcome by its probability and sum them. The mathematically optimal choice is the one with the highest expected value.

Intermediate MathematicsEconomics

Falsifiability

A claim that can't be proven wrong isn't a strong claim — it's an unfalsifiable one. Good theories make specific, testable predictions.

Intermediate PhilosophyGeneral Thinking
⊿⊿⊿

Fat Tails

In some distributions, extreme events are far more common than normal distributions predict. The tails are 'fat' — and that's where the real action is.

Advanced MathematicsSystems Thinking

Feynman Technique

If you can't explain something simply, you don't understand it well enough. Teaching is the ultimate test of understanding.

Foundation General Thinking

Fitness Landscape

Imagine all possible strategies as points on a landscape where height represents fitness. Evolution (and innovation) climbs toward peaks — but can get stuck on local hills.

Advanced BiologySystems Thinking
⊘⊘⊘

Gambler's Fallacy

Believing that past random events affect the probability of future random events — that a coin 'is due' for heads after several tails.

Foundation PsychologyMathematics
◎◎◎

Goodness of Fit

The best model isn't the most complex or the most elegant — it's the one that best fits your specific situation.

Intermediate General ThinkingPhilosophy

Halo Effect

A positive impression in one area creates a biased positive impression in unrelated areas.

Foundation Psychology

Hindsight Bias

After something happens, we convince ourselves we knew it all along — even when we didn't.

Foundation Psychology

Homeostasis

Systems resist change and try to return to their equilibrium state — even when change would be beneficial.

Intermediate BiologySystems Thinking

Hyperbolic Discounting

We strongly prefer immediate rewards over future ones, even when waiting would give us much more. $100 today feels better than $120 next month.

Foundation PsychologyEconomics

Hysteresis

The state of a system depends on its history, not just its current inputs. Damage doesn't always reverse when you remove the cause.

Advanced Systems ThinkingPhysics

Iatrogenics

Sometimes the intervention causes more harm than the problem. The cure can be worse than the disease.

Intermediate BiologySystems Thinking
⊙⊙⊙

Identity-Protective Cognition

We evaluate evidence not by its quality but by whether it supports the identity of the group we belong to.

Advanced Psychology
⊞⊞⊞⊞⊞

IKEA Effect

We overvalue things we helped create, regardless of their objective quality.

Foundation Psychology

Incentive-Caused Bias

Never ask someone for their opinion on something when their income depends on giving you a particular answer.

Foundation PsychologyEconomics

Irreversibility

Some decisions can be undone; others can't. The irreversible ones deserve disproportionate care.

Foundation General Thinking
◉◉

Know Your Audience

The same message lands completely differently depending on who receives it. Effective communication starts with understanding the listener, not perfecting the message.

Foundation Communication

Leverage

Small inputs that produce disproportionately large outputs. Time, capital, code, media, and labour can all be leveraged.

Foundation General ThinkingEconomics
🍋

Market for Lemons

When buyers can't distinguish quality, sellers of high-quality goods exit the market because they can't get fair prices — leaving only low-quality goods.

Intermediate Economics

Mental Accounting

We treat money differently depending on where it came from or what we've labelled it, even though a dollar is a dollar.

Intermediate EconomicsPsychology
⟳⟳

Mere Exposure Effect

We prefer things simply because we've been exposed to them repeatedly — familiarity breeds liking, not contempt.

Foundation Psychology
⊙⊙

Mimetic Desire

We don't want things independently — we want things because other people want them. Desire is borrowed, not original.

Intermediate PsychologyPhilosophy

Minimum Effective Dose

Find the smallest input that produces the desired result. More is not always better — sometimes it's waste.

Foundation General ThinkingBiology
⊘⊘

Moral Hazard

When you're insulated from the consequences of risk, you take more risk.

Intermediate Economics
◉◉

Naive Realism

The belief that you see the world objectively, and anyone who disagrees must be uninformed, irrational, or biased.

Intermediate PsychologyPhilosophy

Negativity Bias

We give more weight to negative experiences, information, and emotions than to equally positive ones.

Foundation Psychology

Network Effects

Some products become more valuable as more people use them — creating winner-take-all dynamics.

Intermediate EconomicsSystems Thinking

Niche Construction

Instead of just adapting to your environment, actively shape it to suit your strengths.

Intermediate BiologyGeneral Thinking

Optionality

Create situations with limited downside and unlimited upside. Keep your options open until you have to commit.

Intermediate EconomicsGeneral Thinking
⊞⊞⊞⊞

Paradox of Choice

More options don't always make us happier — beyond a threshold, additional choices increase anxiety, regret, and decision paralysis.

Foundation PsychologyEconomics

Path Dependence

Where you end up depends heavily on where you started and the sequence of steps taken — not just the destination's inherent qualities.

Intermediate Systems ThinkingEconomics
⊿⊿

Peak-End Rule

We judge experiences primarily by their most intense moment and their ending — not by the average or total.

Intermediate Psychology

Planning Fallacy

We systematically underestimate how long tasks will take, even when we have direct experience of past overruns.

Foundation Psychology

Power Laws

In many systems, a small number of inputs produce the vast majority of outputs. Distributions are rarely equal.

Intermediate MathematicsSystems Thinking

Premature Optimisation

Don't perfect what you haven't validated. Optimising the wrong thing wastes more effort than doing nothing.

Intermediate EngineeringGeneral Thinking
$$

Price Discrimination

Charging different prices to different customers for the same product, based on their willingness to pay.

Intermediate Economics
⊗⊗

Principal-Agent Problem

When someone acts on your behalf, their interests may diverge from yours.

Intermediate Economics

Prisoner's Dilemma

When two parties would both benefit from cooperating but each has an individual incentive to defect, the result is often mutual loss.

Intermediate EconomicsPsychology
⟐⟐

Process vs Outcome Thinking

Judge decisions by the quality of the reasoning, not the quality of the result. Good processes sometimes produce bad outcomes, and vice versa.

Foundation General Thinking
⊣⊣

Reactance

When people feel their freedom is threatened, they do the opposite of what's being asked — even if compliance would benefit them.

Intermediate Psychology
⊡⊡

Reading the Room

Before acting, assess the context, stakeholders, incentives, and power dynamics. The same action produces different results in different rooms.

Foundation CommunicationGeneral Thinking
⊞⊞

Redundancy

Build slack into systems. The backup you never use isn't waste — it's insurance against the failure you can't predict.

Intermediate EngineeringSystems Thinking

Regression to the Mean

Extreme performances tend to be followed by more average ones — not because of any causal force, but because extreme results are statistically unusual.

Intermediate MathematicsPsychology
⊖⊖⊖

Removal as Strategy

Sometimes the best move isn't adding something new — it's removing something that's holding you back.

Foundation General Thinking

Satisficing vs Maximising

Choose the first option that meets your criteria rather than exhaustively searching for the best possible option.

Foundation PsychologyEconomics
⊟⊟

Scenario Planning

Imagine multiple futures, not just one. Prepare for several plausible outcomes rather than betting everything on a single prediction.

Intermediate General ThinkingSystems Thinking

Scope Insensitivity

We fail to scale our emotional response proportionally. Saving 200,000 birds doesn't feel 100x more important than saving 2,000.

Intermediate PsychologyMathematics

Selection Bias

The sample you're looking at isn't random — it was filtered in ways you may not notice.

Intermediate MathematicsPsychology

Signal vs Noise

Most information is noise. The skill is filtering for the signal — the rare data points that actually change your understanding.

Intermediate MathematicsGeneral Thinking
⊗⊗⊗

Single Point of Failure

Any component whose failure causes the entire system to fail. The question isn't whether it will fail — it's whether you've prepared for when it does.

Foundation EngineeringSystems Thinking

Skin in the Game

People with something to lose make better decisions than those who are insulated from consequences.

Intermediate EconomicsPsychology
⊕⊖⊕

Specialisation vs Generalisation

Specialists exploit narrow advantages efficiently. Generalists adapt to change flexibly. The optimal strategy depends on environmental stability.

Intermediate BiologyEconomics

Spotlight Effect

We overestimate how much other people notice our appearance, behaviour, and mistakes.

Foundation Psychology

Status Quo Bias

We prefer the current state of affairs simply because it's familiar — even when alternatives are objectively better.

Foundation Psychology
⟁⟁

Strawman vs Steelman

A strawman weakens an opponent's argument to make it easy to defeat. A steelman strengthens it to ensure you're engaging with the best version.

Foundation CommunicationPhilosophy

Streetlight Effect

Searching for answers where it's easy to look, rather than where the answers actually are.

Foundation PsychologyGeneral Thinking
⊕⊕⊕⊕⊕

Symbiosis

Organisms (and organisations) can form mutually beneficial relationships where both parties gain more together than either would alone.

Foundation BiologyEconomics
⊞≋

Systems vs Goals

Goals are about the end state you want to reach. Systems are about the process you follow every day. Systems-oriented people tend to outperform goal-oriented people.

Foundation General Thinking
⊖⊖

Technical Debt

Quick shortcuts today create compounding costs tomorrow. Like financial debt, technical debt accrues interest — and eventually the interest payments exceed the original savings.

Intermediate Engineering

The Lindy Effect

The longer something has survived, the longer it's likely to continue surviving. Age is a positive signal for ideas and systems.

Intermediate Systems ThinkingMathematics

The Peter Principle

People are promoted based on their current performance until they reach a role they're incompetent at — where they remain.

Foundation PsychologyEconomics

The Scientific Method

Form a hypothesis, design a test, observe results, update your beliefs. The most reliable process for separating truth from opinion.

Foundation General ThinkingPhysics
⊕⊕⊕

Tragedy of the Commons

When everyone has access to a shared resource and acts in self-interest, the resource gets depleted.

Intermediate EconomicsSystems Thinking
?⊙?

Unknown Unknowns

There are things you know you don't know (known unknowns) and things you don't even know you don't know (unknown unknowns). The second category is where the real danger lives.

Intermediate General ThinkingPhilosophy

Via Positiva vs Via Negativa

Improvement by subtraction (removing what's harmful) is often more reliable than improvement by addition (adding what's beneficial).

Intermediate General ThinkingPhilosophy

Wicked Problems

Some problems have no definitive formulation, no stopping rule, and no test for a solution. Recognising them changes how you approach them.

Advanced Systems ThinkingPhilosophy

Winner's Curse

In competitive bidding, the winner often overpays because winning means you valued the item more than everyone else — likely too much.

Intermediate EconomicsPsychology
⊕⊖

Zero-Sum vs Positive-Sum

Some situations have a fixed pie where one person's gain is another's loss. Many situations have an expandable pie where everyone can gain.

Foundation EconomicsGeneral Thinking