Dr. Wallace’s Favorite Mental Models

Via Negativa

Learn it → Apply it → Save as Skill

The fastest way to improve something is often to remove what is hurting it, not to add something new. Knowing that a habit, clause, feature, or ingredient is harmful is usually more reliable than knowing that a new one will help, so subtraction deserves the first look, not the last.

Why This Library Is Different

Learn it. Apply it. Save as Skill.

The Dr. Wallace’s Favorite Mental Models is designed to turn useful ways of thinking into reusable tools. Each model gives you a fast visual overview, deeper interactive learning, practical application exercises and an AI-ready Markdown skill you can save for future use.

Instead of merely reading about mental models, you can gradually build your own AI skills library: a collection of portable reasoning skills that can help ChatGPT, Claude, Grok and other AI assistants apply the mental models you value.

30-Second Understanding
Subtract before you add.

It is usually easier to know that something is wrong, harmful, or unnecessary than to know what new thing would actually help. A diet that removes a harmful ingredient rests on firmer ground than one that adds a trendy supplement. Improvement often means clearing away what is broken, not layering something new on top of it.

Core question: What could I remove, stop, or avoid that would improve this, instead of what could I add?

The memorable shorthand

Low confidence: unproven benefitHigh confidence: confirmed harm gone

Important: via negativa is not "remove everything." It is removing what is confirmed harmful or useless first, before reaching for something new and unproven.

Mental Model Compass

Use it when a system feels cluttered, fragile, or stuck.

The model is most useful whenever the reflex is to add a fix on top of a problem, and you want to check whether removing the problem itself would work better.

Simplify & DecidePrimary use case
BeginnerDifficulty
3 minUnderstand
15–30 minApply to a real decision
Product & UXWriting & editingPersonal habitsNegotiationRisk managementMeetings & process
Model at a Glance

List → Question → Check → Remove.

The method walks from naming everything present to cutting the smallest, highest-confidence set of harmful or useless items.

01List

Write down everything currently present: features, steps, habits, clauses, meetings, ingredients, rules.

02Question

For each item, ask whether it is actively causing harm, adding no value, or just there out of habit.

03Check

Before cutting, confirm why the item exists in the first place. A fence still standing may be doing a job you can’t see.

04Remove

Cut the smallest set of highest-confidence items first, then reassess before adding anything new.

When Should I Use This?

Recognize the situation.

Open a use case to see what the model changes.

Product & UX
A product feels cluttered and conversion is dropping

List every screen, field and step in the flow. Find the ones that do not serve the user's core task and remove them, instead of layering a tutorial or tooltip on top of a confusing flow.

Writing & Editing
A draft feels weak despite another editing pass

Cut redundant sentences, hedging phrases and sections that repeat the same point, rather than adding more explanation to prop up a paragraph that is not working.

Personal Habits
You want to feel sharper and more energetic

Before adding a new supplement, workout plan or productivity app, identify what is already actively hurting your sleep, energy or focus, and remove that first.

Negotiation
A deal keeps stalling despite new concessions

Instead of offering something new to sweeten the deal, identify and remove the specific clause or condition the other side actually objects to.

Risk & Investing
A plan or portfolio feels fragile

Rather than adding hedges or diversification on top of a shaky position, identify and remove the single dependency or assumption most likely to cause ruin.

Meetings & Process
Meetings and approvals keep multiplying

Before adding a new meeting or approval step to fix a coordination problem, find and cut the existing step that no longer serves the purpose it was created for.

Worked Example

An onboarding flow loses 40% of new users. What should change?

This is an illustrative example designed to teach the method.

11 steps
6 steps
Before: full signup flowAfter: essential steps only
SITUATION40% of new users drop off during signup
FIRST INSTINCTAdd a tutorial video, a progress bar, a chat widget
REMOVED 1Three optional fields nobody used downstream
REMOVED 2A verification step duplicated later in the flow
REMOVED 3A marketing opt-in screen inserted by another team
RESULTDrop-off fell to 22% with zero new features built
Do not conclude: "users just needed more help getting through it." The video, progress bar and chat widget might have helped people survive a broken flow. Removing the unnecessary steps fixed the actual problem.
History & Accuracy

A theological term with a modern decision-making life.

Expand for where the phrase comes from and how its meaning shifted.

Where does the term "via negativa" come from?

"Via negativa," Latin for "negative way," comes from apophatic theology, a tradition developed by thinkers such as Pseudo-Dionysius the Areopagite and later the Jewish philosopher Moses Maimonides. It describes the divine by stating what it is not, since human language was considered too limited to positively define it. The original sense is about description, not decision-making.

Who applied it to modern decisions and risk?

Statistician and essayist Nassim Nicholas Taleb adapted the term in his 2012 book "Antifragile." He argued that subtractive knowledge, knowing what is harmful, is generally more robust than additive knowledge, knowing what helps, because a single clear case can prove something harmful while proving something helpful usually requires much broader and shakier evidence.

Is this the same as minimalism or "less is more"?

It overlaps but is not identical. Minimalism is often an aesthetic or lifestyle preference. Via negativa is a decision rule about where reliable improvement tends to come from: it argues for removing confirmed harm before adding unproven benefit, not for owning fewer things as a goal in itself.

Common Mistakes

Subtraction is a discipline, not a slogan.

Treating it as "remove everything"

The model calls for removing what is confirmed harmful or useless, not stripping a system down until it stops working.

Cutting a safeguard because it looks inefficient

Some redundancy exists to prevent a specific failure. Check what job an item is doing before assuming it does nothing.

Confusing "I don't use this" with "no one needs this"

Personal irrelevance is not evidence of uselessness to everyone else relying on the same system.

Adding a fix instead of removing the cause

A new feature, rule or habit built to compensate for a problem often just adds more surface area to maintain.

Removing too much at once

Cutting several things simultaneously makes it hard to tell which specific removal caused the improvement.

Assuming subtraction is always the answer

Some situations genuinely require building something new, not merely clearing away what exists.

When Not to Use It

Some problems require building, not cutting.

Build the missing capability when…

a product, process or plan genuinely lacks something essential that no amount of removal will supply.

Use Chesterton’s Fence when…

you are unsure why an item exists at all. Understand its purpose before deciding whether to cut it.

Use Antifragility when…

the goal is to gain from disorder and stress, not only to remove sources of harm.

Counterpoint: via negativa is not a bias against all addition. It is a rule about sequence: check what you can remove with confidence before reaching for an addition whose benefit is still unproven.
Combine It With

One model rarely does the whole job.

Try It Yourself

Build a Via Negativa analysis prompt.

This browser tool structures your thinking. It does not send your information anywhere or perform AI analysis.

Your AI-ready prompt

Complete the fields, then build your prompt.
Save as Skill

Turn this mental model into a reusable AI skill.

Save as Skill converts the model into portable Markdown instructions that teach an AI when and how to apply Via Negativa, what questions to ask, what evidence to seek, what mistakes to avoid and how to structure its analysis.

Build your own Mental Models Skills Library

Save the skills you find useful and organize them into your own reusable library. The Markdown is intentionally model-neutral, so it can be used wherever an AI system accepts uploaded files, project knowledge, custom instructions or reusable text context. Platform capabilities differ, so this is a portable skill file rather than a claim of one-click installation.

Go Deeper

For readers who want the nuance.

Does via negativa mean addition is always wrong?

No. It is a sequencing rule, not a ban. Check what you can remove with high confidence first, because that knowledge tends to be more reliable, then consider addition once subtraction is exhausted.

How is this different from just being risk-averse?

Risk aversion avoids new bets in general. Via negativa specifically distinguishes the reliability of two kinds of knowledge: what is confirmed harmful versus what is merely hoped to help, and acts on the more reliable one first.

Why does Taleb call this a form of robustness?

A system that survives by removing known sources of fragility depends on fewer untested assumptions than one that survives by stacking new fixes on top of old problems. Fewer untested assumptions generally means fewer ways for a plan to fail in an unexpected direction.