Tree of Knowledge
New information only sticks where you already have branches to catch it
- Difficulty
- Easy
- Time to result
- ~ongoing to results
- Steps
- 5
- Confidence
- 82%
Weitzman pictures all knowledge as a tree. Early life and school build the bark; university and wide reading grow the branches; every book adds a leaf of information. Crucially, a leaf with no branch beneath it simply floats away, which is why unfamiliar facts do not stick. Retention therefore depends on the density of context you have already built. The model explains why business books eventually bore him (his branches are dense) and why he now reads primary sources, why re-reading surfaces new detail, and why isolated ideas that connect to nothing else in your tree, like a conspiracy theory, are a warning sign. Practically, it argues for building foundations first, then going broad, then deep.
Origin
Extracted from Deep Dive with Ali Abdaal. Weitzman offers the tree as his answer to critics who ask what the point of reading 100 books a year is if you don't act on every one.
Core principles
- 01Knowledge is a tree: foundations are bark, disciplines are branches, facts are leaves
- 02A leaf with no branch to land on floats away
- 03Density of context determines what you retain
- 04Ideas disconnected from your main tree are how conspiracy shrubs grow
- 05Start broad and shallow, then go deep and connected
How to run it
- 1
Lay down the bark
Get the foundational context of a subject first, from school, conversation or an introductory overview.
Pro tip For an unfamiliar field, a broad audiobook builds the trunk before you attempt experts.
- 2
Grow the branches
Read broadly within the topic so you have structure for detail to attach to.
Pro tip Ten well-understood books beat a hundred half-retained ones early on.
- 3
Add leaves in dense areas
Once branches exist, each new book lands and stays. Notice how much more you keep when reading in a familiar density.
Pro tip If facts keep floating away, your branches are too thin; reinforce the basics.
- 4
Go deep to primary sources
When a topic starts feeling repetitive, you have saturated the popular layer; move to primary sources and re-reads.
Pro tip Re-listen to favourites yearly; new context catches detail you missed before.
- 5
Audit disconnected ideas
Treat beliefs that connect to nothing else in your tree with suspicion; that is how isolated conspiracy shrubs form.
Pro tip Ask how a new claim links to what you already reliably know.
Watch out Novelty without connection is a red flag, not a discovery.
In the wild
Weitzman has listened to the entire Bible in Hebrew several times. He points out that quoting a line from the Book of Numbers to someone with no Hebrew or scriptural context is pointless, they will not remember it five days later, because the leaf has no branch to land on. The same words land richly for someone who has built the surrounding foliage.
→ Illustrates that identical information is retained or lost depending entirely on pre-existing context.
Weitzman once believed Vikings were mythical, like dwarves and elves. On a trip to Copenhagen a local spoke of them as historical figures, and learning that King Bluetooth was a real person suddenly slotted Vikings into his mental map of the world, connecting them to other history he already held.
→ A single anchoring fact integrated an entire topic into his existing tree of knowledge.
Common mistakes
Chasing leaves before branches
Consuming advanced material with no foundation means almost none of it is retained.
Trusting disconnected ideas
A belief that links to nothing else you know is a shrub, not part of your tree, and deserves scrutiny.
Is it for you?
Best for
Self-learners deciding what to study next and how to sequence broad versus deep reading.
Not ideal for
People seeking a step-by-step productivity system rather than a way to think about retention.
From the transcript
“All the knowledge in your brain is like a tree... every book you read is a new leaf of information on that tree. Now if…”
“If the mental model is that gigantic tree, that conspiracy theory is a shrub that lives over here that's not connected to your main tree…”
From the episode
You're Not Lazy: How To Learn Anything Faster - Cliff Weitzman Founder of Speechify
Cliff Weitzman