Header image featuring Plato, Einstein, and the author

This is the handbook's overview. Start at page one.

Critical thinking

We'll be using three critical thinking tools to help us make sense of the world: 

This page introduces these tools. The next page shows you how to leverage them to reliably win personal, business, and political arguments. And to think much bigger.

By the end of this guide, you'll know how to:

The three tools


Logical fallacies ("fallacies") are tricks used to:

In either case, you're likely using a fallacy because you lack evidence for your position.

Here's an example: While pushing a post-9/11 anti-terrorism agenda, U.S. President Bush said, "You are either with us or you are with the enemy." 

(On the next page, I'll show you Obama and Clinton committing silly fallacies.)

Obviously no one would choose the terrible path (being with terrorists), so Bush hoped you'd abandon critical thinking and settle on his "only" path: a proposal to wage war.

But, there are many more paths beyond full-on war, including sanctions, negotiations, and more surgical warfare strategies.

So when he tries tricking you to reflexively believe there are only two paths, he's deceiving you with a fallacy. This particular fallacy is called The False Dilemma. It's handy when you lack evidence to actually prove your conclusion is good.

If you're tired of hearing bad arguments like this and not knowing how to immediately respond with counterexamples to win the argument, you're lacking an awareness of the most common fallacies. We'll learn them on the next page. They include:

(We'll learn techniques to fully refute these types of bad arguments.)

Every day, I notice brilliant authors and bloggers committing fallacies. These routine brainfarts demonstrate that arguing well is not the result of IQ. It's the result of not being taught critical thinking as kids. So, we remain ignorant even if we're brilliant.

However, fallacies are only the tip of the iceberg. Biases are where bad logic is born.


Cognitive biases are what we're pre-motivated to believe and disbelieve. 

We rely on biases as shortcuts when forming conclusions: Instead of looking at all the evidence, we go with what "feels" right. 

We do this because having to consider all the evidence is tedious. Or because we're confident our existing view is right and that more evidence is unnecessary.

Examples of suffering from bias include blindly adhering to a political party's doctrine, being "absolutely convinced" you saw a UFO, and readily believing most stereotypes.

If you know how to identify biases within someone's argument, you can explain why they're wrong. It's one thing to easily refute their bad logic (fallacies), but it's another to talk them through their reasoning. That's the only way to change how they think. 

Exploiting someone's biases is in part how you become a remarkably persuasive writer. And a commanding leader. In fact, when you combine an understanding of biases with an understanding of persuasive speech, you can convince most people of anything.

So we'll learn how to do this in a couple pages from now.

If you contemplate why everyone talks in politics but no one listens, what you're actually wondering is, How do we prevent people from relying on their biases? 

Further, when you understand biases, you can avoid them yourself. So your conclusions get closer to the truth. You get a taste of Musk-level decision making. Although, you'd still need one more thing to get there: models. Let's introduce them.

"The trouble with the world is that the stupid are confident and the intelligent are full of doubt."
‚Äď Bertrand Russell


Biases and fallacies are what we watch out for to avoid forming bad conclusions, but mental models are what we use to propose brilliant conclusions to begin with.

Models are simply frameworks for identifying the best data and shaping it into a viable conclusion. When we follow the structure of a model, we lessen the odds of accidentally relying on biases and fallacies. We systematically become insightful.

Here's an example: The First Principles model is what Elon Musk currently uses to derive engineering insights for Tesla and SpaceX.² Its approach is to dismiss convention to increase the odds of discovering something others have overlooked. 

It instructs you to begin examining a situation at its lowest-level, undeniable facts. For example, if you want to determine whether there's a cheaper way to build batteries, you could start by researching the cost of batteries' raw materials (e.g. nickel, cobalt.)

In doing this, Elon discovered he could drastically reduce the cost of materials by partnering with the companies that mined them from the ground.

In contrast, he wouldn't have started by examining the cost of pre-fabricated battery cells. That would be a higher-level abstraction that would mislead about the true, low-level costs of batteries. 

Once you've identified¬†the lowest-level facts, you methodically layer increasingly higher-level facts ‚ÄĒ not assumptions ‚ÄĒ atop one another until you reach a discovery.¬†

Meanwhile, you give a big middle finger to what everyone else is doing.

What I've just described is all there is to First Principles; that wasn't an abridged version. A model isn't in any way complex. It's just a fancy name given to a framework used for examining evidence to arrive at a reasonable conclusion. 

(You'll soon learn the specific steps for applying this model to your own goals. In fact, you'll learn all the best models for making insightful personal and business decisions.)

Mental models are what the sage elders of history and literature use to impart their wisdom. Consistently using these frameworks to interpret the world is what makes you appear wise and insightful. It helps you see through all the clutter.

As a quick teaser of what's to come, here's how Jeff Bezos created his own mental model to justify starting Amazon.com:

My argument

This guide's central argument is that the most significant learnable difference between you and the people you think are smarter is the everyday use of these three tools.

We're about to explore the basics of each: We'll learn how to refute the ten common fallacies so we can WWE smackdown¬†ūüĎä bad arguments, how to identify biases so we can change people's minds, and the five¬†models that make us¬†insightful¬†ūü§Ē

I'll even share audio of me using these skills to debate friends on whether Edward Snowden should be pardoned, whether the death penalty should exist, and more.

But before we begin, let's learn what an argument actually is. It'll only take us a minute.

Wait, what's an argument?

ūü§Ē All material for the remainder of this guide is¬†summarized in a comprehensive cheat sheet at the bottom of the last page. There's no need to take notes.¬†

To form an argument, you identify evidence to support premises you believe to be true. Then you use those premises to propose a conclusion:

  1. I have evidence that Premise 1 is true.
  2. I have evidence that Premise 2 is true.
  3. Therefore, I conclude X.

For example:

  1. I have evidence that CO2 emissions cause global temperatures to rise.
  2. I have evidence that some natural disasters result from global temperatures rising.
  3. Therefore, I conclude reducing CO2 emissions will help keep humanity safe.

For a premise to be proven valid, you need evidence supporting it. The more your evidence adheres to the scientific standard, the stronger it is. That standard consists of rigorous experimental testing that withstands scrutiny from qualified third-parties.

If your premises are valid and the logic used to reason from your premises toward your conclusion doesn't suffer from a fallacy, your conclusion is sound. 

Since we must know someone's evidence, premises, and conclusions to figure out what's wrong (or right) with their arguments, we'll use the framework below to get them to share exactly what's going on inside their head.

The argument framework

When someone presents an argument, consider using this framework to the extent you're interested in ensuring their reasoning is sound. In short, you'll want to sanity check their evidence, premises, and conclusion:

  1. Ask them to clearly state their conclusion.
  2. Ask what premises ("reasons") lead to their conclusion.
  3. Ask what evidence they have to support their reasons.
  4. Check their conclusion against the list of fallacies. Refute any fallacies that exist.
  5. If the argument still seems fishy, check their evidence against a shortlist of biases. Point out any that exist. Explain that any premises built on these biases must be re-examined.

If biases or fallacies exist, you can use a model to re-examine their evidence and help generate a new, better conclusion!

Diagram of how evidence can be used to feed bias, intuition, or a mental model

Continue to fallacies

Let's learn the common fallacies, biases, and models.

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