# One Simple Idea

> ### _“We Model the World, and the World Models Us.”_

#### -Karl Friston

This is a principal idea introduced in the [Free Energy Principle](https://en.wikipedia.org/wiki/Free_energy_principle) developed by neuroscientist Karl Friston, though it is rooted in philosophical origins as many concepts are. Initially designed to study the brain, the Free Energy Principle is a formal statement that explains how _any_ _**self-organizing**_ **living** or **non-living** system that is at _**equilibrium with its environment**_ must **minimize its Free Energy**.

And that necessitates _**generating**_**&#x20;Models of the World**.

### What are Models of the World?

They are **Representations**, as the German philosopher Arthur Schopenhauer described in [_The World as Will and Representation_](https://en.wikipedia.org/wiki/The_World_as_Will_and_Representation). The world as we experience it,

> _“exists solely as ‘representation’ dependent on a cognizing subject, not as a world that can be considered to exist in itself – without the subjective experience within one’s mind.”_&#x20;

These concepts advance the works of thought leaders like [Immanuel Kant](https://en.wikipedia.org/wiki/Immanuel_Kant#Young_scholar), who was himself influenced by logicians and philosophers before his time.

![Have you ever questioned the nature of your reality?](https://3692130413-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2Fethereum-a-model-of-the-world%2F-MW0_pKNKmrBVQQB6JZC%2F-MW0aDclyOwnjYabKiLL%2F0.gif?generation=1616008244676777\&alt=media)

While these thinkers reasoned _logically_ and _philosophically_ that such a system of representations must exist for our **experience of the world**, the Free Energy Principle attempts to **objectify** such frameworks through _**math**_ and _**statistics**_.

Because this notion is so abstract, it is better elucidated through narrative, example, and analogy. For instance, 71% of the Earth’s surface is water. The most vital organs in our body also roughly have a 71% water composition:

![](https://3692130413-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2Fethereum-a-model-of-the-world%2F-MW0_pKNKmrBVQQB6JZC%2F-MW0aDcmqaVjjoGRlpPK%2F1.png?generation=1616008244674004\&alt=media)

It can be tempting to chalk this up to chance, but a deeper connection is realized through the lens of the Free Energy Principle.

![](https://3692130413-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2Fethereum-a-model-of-the-world%2F-MW0_pKNKmrBVQQB6JZC%2F-MW0aDcnP7xPaT7afJv5%2F2.png?generation=1616008244595600\&alt=media)

### So, what is Free Energy?

Put simply, it is the **maximum** **amount of energy** _**available**_ for **work**. Within the Free Energy Principle framework, it is more specifically _**Variational**_**&#x20;Free Energy**. The definition can be prohibitively technical because it includes terms like the _Kullback-Leibler divergence, Laplace approximation, ensemble densities_, and related jargon to formally state what is illustrated here ([source](https://www.fil.ion.ucl.ac.uk/~karl/The%20free-energy%20principle%20-%20a%20rough%20guide%20to%20the%20brain.pdf)):

![](https://3692130413-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2Fethereum-a-model-of-the-world%2F-MW0_pKNKmrBVQQB6JZC%2F-MW0aDcoUwnWOWgqTWya%2F3.png?generation=1616008244649777\&alt=media)

Fortunately, there is an _**intuitive**_ and _**conceptual**_ way to understand these technicalities. Before diving into the Free Energy Principle to understand how Ethereum is a Model of the World, we will review a concept so **fundamental** that it pervades the **Hierarchy of Sciences**:

![](https://3692130413-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2Fethereum-a-model-of-the-world%2F-MW0_pKNKmrBVQQB6JZC%2F-MW0aDcppX4Jw7u3bGDD%2F4.png?generation=1616008244628882\&alt=media)

**First principles thinking** leads the way.
