The Feynman Technique: If You Can't Explain It Simply, You Don't Understand It
Richard Feynman was one of the most brilliant physicists of the 20th century.
He was also one of the most effective explainers. Not just to experts, but to anyone.
And he believed these two qualities were inseparable.
"If you can't explain it simply, you don't understand it well enough." — Richard Feynman
The Feynman Technique isn't a memorization hack. It is a ruthless test of genuine comprehension.
📋 The Four Steps
Choose the concept
Pick the idea, principle, or topic you want to understand. Write the name at the top of a blank page.
Explain it to a child
Write out the concept as if you are teaching it to a 12-year-old. No jargon. No technical shortcuts. Plain language only. This is the hard part — and deliberately so.
Identify the gaps
Wherever you hesitate, stumble, or reach for technical language — that is where your understanding is weak. Those gaps are the most valuable thing this exercise produces. Go back to the source material and study exactly those gaps.
Simplify and use analogies
Once you've filled the gaps, rewrite your explanation. Use analogies. Use stories. Connect the new concept to something the "child" already knows. If you can do this, you own the idea.
🔍 Why Jargon Is a Warning Sign
Jargon is useful for communication between experts. But when you are learning, over-reliance on technical language often signals a problem.
It signals that you have memorized the vocabulary without internalising the idea.
Without Feynman
"Photosynthesis is the process by which photoautotrophs convert light energy into chemical energy stored in glucose via the Calvin cycle."
Can you explain why that matters? What it actually looks like? What fails when it doesn't happen?
With Feynman
"Plants are like solar panels that make their own food. They use sunlight to turn water and air into the sugars that power every cell in their body. Without this, almost all life on Earth would collapse."
Now you understand it. And you could explain it to anyone.
🔗 The Connection to Active Recall
The Feynman Technique is active recall at its highest level.
Flashcards test whether you remember a fact. The Feynman Technique tests whether you have truly understood a concept — deeply enough to rebuild it from scratch in your own words.
Use both. They work at different depths of understanding.
If you can teach it clearly, you know it truly.