# A Short and Simple Introduction to Entropy

## Learn this mental model in just a few minutes

If you harbor the desire to have some idea what others mean when they mention **entropy** (or maybe even use it in a sentence yourself) — read on! Entropy is a mental model well worth learning.

# What is entropy?

Entropy is a concept from physics that initially stemmed from some ideas a guy called Rudolf Clausius had around thermodynamic processes.

The purists may hate me for this, but I’m going to really simplify the concept so that we can cover it in this short post. The goal here isn’t to understand to the level of a physicist or chemist, but just to be able to wrap our heads around entropy enough to be able to add it to our latticework of mental models!

Here’s a starting definition:

Entropy is a measure of complexity (order or disorder) in a system.

The greater the level of disorder the higher the entropy.

This example from Study makes it clearer:

Let us say you have a bag of balls. You grab one ball from the bag and put it on the table. How many ways can you arrange that ball? The answer: one way. What if we grab two balls and ask the same question? Now there are more ways to arrange the two balls. We keep doing this until all the balls are on the table. At this point, there are so many ways to arrange the bag of balls, you might not even be able to count the number of ways. This situation is very much like entropy.

In this situation, entropy is defined as the number of ways a system can be arranged. The higher the entropy (meaning the more ways the system can be arranged), the more the system is disordered.

**Why is this interesting?**

The interesting thing about entropy is that it’s always increasing. Everything in our universe naturally tends towards disorder. Think about simple systems, such as your bedroom or garden. I can’t be sure, but I suspect if unmanaged, your bedroom — like mine — tends towards being increasingly messy. Similarly in a garden, your neat garden beds tend towards becoming increasingly weed ridden.