The universe's complexity can be understood by three trees: the tree of molecules, the tree of life, and the tree of ideas.
These trees are created by three building block alphabets: elements, genes, and memes (language).
Let's look at each.
I. Elements Create The Tree of Molecules
14 billion to 4 billion years ago
The universe began in a Big Bang fourteen billion years ago. This created a universe full of hydrogen and helium. Through gravity, these simple atoms grouped together to form massive stars. These stars exploded in supernovas to create the elements in the periodic table.
Through the electromagnetic force, these elements combined to form larger molecules like H2O (water) or NaCl (salt).
A few of these elements are especially good at forming bonds with each other. For example, carbon can link up with itself to large massive lattices like graphene.
We call these "easily bondable" elements "organic" elements because they are the basis for the structures of life. They are Hydrogen, Carbon, Nitrogen, Oxygen, Silicon, Phosphorus, and Sulfur.
There are an infinite amount of ways these organic elements can combine in 3D space. We call this the Tree of Possible Molecules. Chemists call it chemical space:
The above image is a visual representation of all the different kinds of organic molecules: proteins, sugars, and much more.
As shown in the image below, we can think of this as a small alphabet of foundational building blocks (elements) creating a tree of complexity (molecules).
II. Genes Create The Tree of Life
4 billion years ago to 200,000 years ago
Most of those infinite molecules weren't special. They were just simple combinations of random elements, floating in the vastness of space. But then, four billion years ago, on a random planet, just the right distance from a star, in liquid water, something special happened. A molecule began self-replicating, using the energy from underwater sea vents. How exactly did this happen? We don’t truly know. It doesn’t look like much but is actually the start of something much bigger. The beginning of genes creating the tree of life.
DNA is a molecule that contains the instructions for creating more of itself. These instructions aren’t written on paper or stored on a computer. Instead, they are represented by a series of molecules, connected into a double helix. Strangely, DNA only has four types of molecules—cytosine, guanine, adenine, and thymine—C, G, A, and T. CGAT is the alphabet for the language of life. Arrange them in one way and boom, a kitten. Change a couple (million) letters and boom, a puppy.
Again we see the same pattern as above: a small alphabet of foundational building blocks (genes made of CGAT) creating a tree of complexity (life).
Although there's an underlying pattern, there are differences between these two trees. Elements take existing matter to create new things, like turning hydrogen and oxygen into water. In contrast, genes take an organism and create more of itself. Elements combine, genes replicate.
Because the genes that don't want to replicate die out, there is an emergent "desire" to replicate. Organisms seem to have a "purpose," to reproduce. Stars don't. I wish that stars wanted to create cute little star babies, but they don't. They just are. The universe abides by laws of physics, not some deeper purpose.
III. Memes Create The Tree of Ideas
200,000 years ago to today
After four billion years of life, the first homo sapiens emerged around 200,000 years ago.
Sapiens are just a small part of the tree of life. However, we developed something special, spoken language. We don’t know exactly how language evolved, but it set us apart from other animals. It allowed us to communicate and spread ideas like “ug, tiger over there.”
Language looks surprisingly similar to genes. Spoken language has a small set of roughly 50 phonemes that our vocal tract can produce—from “ahhhhh” to “ch.” Written language has small alphabets too; the English alphabet has 26 letters. And yet, like genes, this small alphabet can be used to describe an infinite variety of thoughts from “god is great” to “god is just fine.”
These thoughts, called memes, self-replicate to spread through minds, written text, and the internet. They create the tree of ideas, the memesphere.
Like genes, these memes have this same emergent "purpose", to replicate. But actually this is just because all the non-replicators die. We're left with only proselytizing religions and catchy songs.
IV. Modular Building Blocks Create Trees Of Complexity
Taken together, we can put these three trees side by side. They tell the stories of cosmic evolution, biological evolution, and human evolution.
Each have the same pattern.
A small alphabet of foundational building blocks create a tree of complexity.
- 10 Organic Elements create The Tree of Possible Molecules
- The 4 letters (CGAT) of genes create The Tree of Life
- The 50 phonemes of language and memes create The Tree of Ideas
This leads to other questions like:
- How does the tree of life evolve?
- How does the tree of ideas evolve?
- Do bits create The Tree of Algorithms?
We'll answer those in a future post. For now, thanks for reading and let me know if you have any feedback.
- This piece is heavily inspired by ideas in two books. First, The Origins of Life by John Maynard Smith introduced the concept of infinite heredity. This is roughly similar as genes creating a tree of life and memes creating a tree of ideas. Second, the Beginning of Infinity by David Deutsch introduces the idea of reach. He primarily uses this for knowledge (2+2=4 is true across the entire universe). But also lightly applies it to small symbol sets like genes and language having large reach (genes code for simple life 4B years ago but also complex life today).
- This is actually my favorite chemical space image. If you want to truly understand how the tree of molecules works, make sure you understand the subgroups of this image. They're all pretty simple. (Carbon chains, DNA, and proteins.)
- The image above shows why it'd be so hard to create life without carbon. Silicon is the only other option, but it has lots of issues like it doesn't create stable chains with itself (decreasing the tree of possibilities).
- This is a great stack exchange answer on how large chemical space really is: https://chemistry.stackexchange.com/questions/16944/how-many-unique-molecules-exist-and-how-many-exist-only-by-synthesis/16955
- This is the best article to understand how we go from DNA to RNA to amino acids: https://berthub.eu/articles/posts/reverse-engineering-source-code-of-the-biontech-pfizer-vaccine/
- As that article mentions genes actually code for twenty amino acids, which then fold into proteins. See macromolecules as a way to translate between the smaller alphabet and larger alphabet.
- Language has a clearly defined way to determine meaning from symbol set: grammar. We can take words, apply rules to them, and get a meaning. On the other hand, genes aren't as simple. Protein folding is how we go from genes/amino acids to actual proteins. We used to not be able to predict protein folding. The rules were too complex. But now with AlphaFold, we're getting much closer.