Multiplying by Zero: Fixing the Weakest Link

08.03.2019 |

Episode #9 of the course Mental models: How to make better decisions by John Robin


Welcome to our second to last day!

You might be enjoying this course a lot so far. I hope that’s true! But all it takes is one bad lesson, even at the end, for the course to fall apart, right?

For today, I promise I won’t let you down! In fact, I’m not telling you this because I have stage fright. It’s because today’s mental model is all about how, many times, no matter how great something seems, it only takes one critical failure to ruin the whole.


What Is Multiplying by Zero and Why Is It True?

You probably remember from math that any number multiplied by 0 is 0.

Multiply a bunch of numbers together. No matter how big the other numbers are, if one of them is 0, the whole product is 0.

For example:

1 × 2 × 3 × 4 × 5 × 6 × 7 × 8 = 40,230

But if I change any of those numbers to 0 (say that I change the 6), I get:

1 × 2 × 3 × 4 × 5 × 0 × 7 × 8 = 0

Another way to look at this is a common analogy:

A chain is only as strong as its weakest link.

The Multiplying by Zero mental model is all about how we tend to think about outcomes. Outcomes depend on two kinds of systems:

• additive

• multiplicative

In an additive system, it’s not a big deal if one thing fails. Take a great party. You might have seven types of drinks, five different appetizer platters, 25 guests invited, four planned games, 100-plus CDs of music lined up, and an order of 30 pizzas on the way. If the pizza order doesn’t show up, there’s still lots at the party and you can hopefully overlook it.

In a multiplicative model, everything is interdependent. Let’s imagine planning your party, for example. Say all the items above listed are what you want to have. Another component is the money. Let’s say you’re broke and have no money at all. Suddenly, the party plans flatline.

We tend to assume most things are additive when they are in fact multiplicative. The result is the Multiplying by Zero effect.

Think about what I said about this course above. Let’s say I have a lesson you don’t care for, but overall, you walk away feeling like you learned more about mental models and enjoyed most of the lessons. This is thinking additive.

Let’s say that through every lesson, I annoy you so much that you stop reading after two paragraphs. This is thinking multiplicative. The value of this course is about more than just any given lesson. There are many interdependent factors, any one of which can spoil the whole. If I flop today’s lesson, well, it’s Day 9 and you’ve made it this far (please forgive me!). On the other hand, if I flopped Day 2’s lesson, you might not make it here to read this right now.


Applying Multiplying by Zero

Think of one aspiration in your life, something you keep putting on hold.

Something is happening to stop it in its tracks. You might apply the umbrella term “procrastination” or just think you don’t have enough time, but in fact, there’s often one very specific thing that’s happening to stop you from succeeding.

Let’s say that you want to start a business on the side. Every day at work, you think about doing it. By afternoon, your head is teeming with all the ideas of what you have to do. You even make notes on your coffee breaks. Then every evening after work, you’re burned out and never get anything done. “I’ll do it tomorrow,” you say. There are good things on Netflix, after all.

You’re using the Multiplying by Zero model here. All your notes, planning, and enthusiasm multiply to nothing if the drive to do isn’t there.

If you want to reverse the problem, you have to address the ZERO in the equation and make it nonzero.

Apply Inversion, since we now have this mental model.

Instead of saying, “Why can’t I get motivated in the evening?” say, “What can I do to make progress every day?”

It might be making a simple rule that you aren’t allowed to go to bed until you’ve spent at least 20 minutes on your endeavor. This way, the ZERO in the equation is addressed, and even if it’s small progress, it doesn’t turn your whole feat into nothing.



The Multiplying by Zero mental model allows you to analyze failure differently. Instead of seeing just failure, you can look at what specific component is causing the problem, then use Inversion to strengthen that weakest link.


Take one goal you have every week that you always feel you fail at. Try to find the ZERO, then invert the problem, using your homework exercise from Day 7.

Tomorrow, we’ll move on to our final day, covering a mental model that tells us how complaining steals the true power from our decisions and how to stop it.


Recommended book

Zero to One: Notes on Startups, or How to Build the Future by Peter Thiel (founder of PayPal)


Share with friends