I used to read whatever book sounded most interesting at the time, no matter the topic. I might jump from a book on climate change to a book on nutrition to a book on finance to a book on goal setting. The benefit was that it allowed me to take concepts from all sorts of different areas, and connect the dots between them to see patterns and similarities. Even if I was really interested in a topic, I would usually stop myself from continuing to read books on that topic for a while, for fear of selling myself short on breadth. It's like I had FOMO of what other knowledge I was missing out on in other disciplines. The downside of bouncing around like this was that I never built momentum in any particular topic. One book is not enough to become well versed on a topic, and the typical modern nonfiction book does not allow for foundational understanding of a given discipline.

When it comes to learning, I always go back to the tree analogy. I first heard it from Elon Musk [1]:

I think most people can learn a lot more than they think they can. They sell themselves short without trying.

One bit of advice: it is important to view knowledge as sort of a semantic tree — make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to.

Reading these words from Elon (my business prophet) was an epiphany for me. I realized I had been learning all wrong. I was going around gathering a bunch of leaves (modern nonfiction and most internet articles) instead of focusing on my roots and trunk. Without first learning and thoroughly understanding the core ideas (or "first principles" as Musk would call them), which act as the roots and trunk of a knowledge tree, my leaves had nothing to hang on to. So I would read about a concept, but only semi-learn it since I didn't REALLY understand it (I had no foundational knowledge trunk from which it could grow), and then move on to the next concept. It didn't take long for most of what I read (the leaves) to vanish since there was no branch for them to grow from. I expected to have this new knowledge just hang in the air as an isolated concept that I needed to remember and be able to reference.

Here are a couple examples of concepts on the knowledge tree:

Physics (roots) > Chemistry (trunk) > Biochemistry (branch) > Biology (twig) > Nutrition (leaf)

World history (roots) > History of the Middle East (trunk) > History of Iran (branch) > What's going on in Iran (leaf)

You can certainly be knowledgeable on a topic and have somewhat of a grasp without the entire tree behind you. You can have an opinion on Iran's recent actions or whether saturated fat is good for you, but the further down the tree your knowledge starts, the more you'll really understand the question or topic at hand.

Yesterday, Renee pointed out this sentence to me in the psychology book she was reading: "In 1873, when Freud was seventeen, the German archaeologist Heinrich Schliemann put together clues from fragmentary historical literary sources and located the ancient city of Troy on the coastal plane of what is now Turkey." Fortunately, Renee had read Freud's work and knew of Schliemann. She had also recently started reading a book on the history of the ancient world and we had just visited the Troy exhibit at the British Museum. If it weren't for those things, that sentence would have meant very little to her. How many sentences do we read without actually understanding them? I'm definitely guilty of reading beyond my pay grade, when I should first understand the underlying principles of the topic.

When I started being fascinated by nutrition, I read all of the books I could get my hands on by modern day citizen scientists and influencers (e.g. Amazon bestsellers in Nutrition). The problem was I didn't have a scientific background to hang a lot of these concepts on, so I kinda just had to trust them and whoever had the best argument would win, and that was frustrating when I couldn't recall why exactly I ate a certain way or avoided certain foods. I ate vegetables because I thought they were healthy, but that was just a leaf, and I couldn't recall the twig or branch that led me to "know" that vegetables are healthy. If someone on the street dubiously asked me why vegetables are healthy, I wouldn't have been able to give a very convincing answer.

So I hit the reset button, and started over in my quest to learn about health and nutrition, and every time I encountered a word or concept I wasn't familiar with, I realized I had to go deeper; I wasn't foundational enough yet. I thought reading about human cells was first-principled enough to understand how the human body works, that seemed like the smallest unit of relevant measurement, but then I realized that I didn't really understand what all these molecules were that made up the cell, so I found my way into chemistry, re-learning the periodic table of elements. But where did these elements come from and why do they act the way they do? I kept using this line of questioning until I got into physics, and finally elementary particle physics. Particle physics seemed like the end of the road. String theory and vibrations were as far as I could go; any deeper would be more philosophy than science.

Getting from nutrition to particle physics took all of a few hours. It was like a roller coaster ride of Wikipedia links that only goes down, continually faster and deeper into the obscure and unknown. Upon reaching the bottom, the way up is slow and arduous. Whereas it only required a few mouse clicks to go from trying to understand physics to realizing I wanted to understand the underlying particle physics first, the journey from particle physics back up to physics required days of trying to understand photons, electrons, gravity and radiation (and of course, days is not nearly enough to "understand" particle physics, but I felt that I had covered enough territory to not be completely clueless on the subject).

I've not been consistent or thorough enough, but I've made an effort to continually work my way up and down the tree of knowledge, trying not to spend too much time on leaves unless they have a branch and trunk to hold on to.

Picking a quarterly or annual reading theme (depending on the depth of the topic) has allowed me to more easily do deep dives into areas of interest, knowing I have a plan and have decided that this particular topic is the most important one for me to explore. It doesn't mean that 100% of what I read MUST be on the topic of my theme, but something like 60-75% is probably a good target. In other words, for every two or three books on my theme, I read one book not related to my theme.

Last year I started reading philosophy and soon realized that the writings of Seneca and others were not as powerful without context on the time they lived in, so I started reading ancient history (my theme for this year). I've coupled learning about ancient history with listening to 20 minutes of world news every day (what happened in the last 24 hours) in an effort to motivate myself to continue learning about what has happened in the last 10,000 years. I've enjoyed connecting the dots between how the world was built thousands of years ago and how it works today. The more I learn, the more there is to learn, and that's part of what makes it so fun.