My whole life I’ve been trying to understand how the world works. How do planes fly? How do computers compute? How does the economy coordinate?

Over time I realized that these questions are all different ways of asking the same thing: how do complex systems work?

The past few years I’ve had the opportunity to spend thousands of hours practicing programming and studying computers. I now understand, in depth, one complex system. I feel I can finally answer the general question about complex systems with a very simple answer.

Compounded Probability Makes Complex Systems Work

There is no certainty in life or in systems, but there is probability, and probability compounds.

We can combine the high probability that wheels roll, with the high probability that wood supports loads, to build a wooden chariot that has a high probability of carrying things from point A to point B, which has a high probability of giving us more time to innovate, and so on and so forth…

Everything is built off of probability. You are reading this because of countless compounded probabilities like:

• There is a high probability that your Internet connection works
• There is a high probability that my web server is responding to connections
• There is a high probability that my web server’s disk works
• There is a high probability that my web software works and will handle this post
• There is a high probability that my Internet connection works
• There is a high probability that my text editor won’t fail as I write this
• There is a high probability that my laptop works
• There is a high probability that the CPU in my laptop consistently adds numbers in the registers correctly

Complex systems consist of many, many simple components with understood probabilities stitched together.

How does a plane fly? The most concise and accurate answer isn’t about aerodynamics or lift, it’s about probabilities. A plane is simply a huge system of compounded probabilities.

How does a bridge stay up? The answer is not about physics, it’s about compounded probabilities.

How do computers work? Compounded probability.

How do cars work? Compounded probability.

The economy? Compounded probability.

Medicine? Compounded probability.

It’s probability all the way down.