The Feynman Technique: How to Actually Learn Anything
The Short Version:
To really learn something, try to explain it like you're teaching a 12-year-old. Wherever you get stuck, that's what you don't actually understand yet. Go back and fill that gap. Repeat until it's crystal clear.
I used to think I understood things just because I could recognize them. I'd read a chapter on neural networks, nod along, and think "yeah, I get it." Then someone would ask me to explain backpropagation and I'd freeze.
That's the illusion of knowledge. And Richard Feynman had the perfect cure for it.
The four steps
1. Pick a concept
Choose something you want to understand. Not vaguely — specifically. Not "machine learning" but "how does a decision tree split data?"
2. Explain it like you're teaching a child
Write it out in plain language. No jargon. No hiding behind technical terms. If you write "the algorithm optimizes the loss function via gradient descent," stop. A 12-year-old doesn't know what any of those words mean.
Instead: "The computer makes a guess, checks how wrong it was, and adjusts its guess to be a little less wrong next time. It does this thousands of times until it gets really good."
3. Identify your gaps
Wherever you struggle to explain simply — that's your gap. You don't actually understand that part. Go back to the source material and fill it in.
4. Simplify and use analogies
Once you can explain every piece simply, organize it into a clean narrative. Use analogies. The best explanations connect the unknown to the known.
Why this works
The technique works because it forces active recall — the most effective form of learning. You're not passively reading. You're actively reconstructing knowledge from scratch.
It also exposes a universal truth: complexity is often a mask for confusion. When someone uses ten jargon words to explain something, they might not understand it either. Simplicity requires depth.
How I use it daily
Every time I learn something new — a paper, a framework, a concept — I write a "simple version" summary. Two sentences max. If I can't write those two sentences, I haven't learned it yet.
That's why every post on this site starts with a "Simple Version" box at the top. It's my forcing function. If I can't summarize it for you in two lines, I need to go back and study more.
The meta-lesson
Feynman wasn't just a physicist. He was a teacher. And his deepest insight wasn't about quantum mechanics — it was about learning itself:
"The first principle is that you must not fool yourself — and you are the easiest person to fool."
The Feynman Technique is a tool for intellectual honesty. Use it, and you'll never confuse recognition for understanding again.