The Feynman Technique: If You Cannot Explain It Simply, You Do Not Understand It Yet
A four-step method named after physicist Richard Feynman that reveals the gaps in your understanding. Use it for any subject, from physics to finance.
You read a chapter, nod along, and feel you understand. Then someone asks you to explain it, and the words disappear. That gap between recognising and understanding is what the Feynman Technique is designed to expose.
The idea
The method is named after Richard Feynman, the Nobel Prize-winning physicist famous for explaining complex ideas in simple language. He believed that if you cannot explain something simply, you probably do not understand it well enough. The four-step version below was popularised later by writers on learning, rather than written by Feynman himself, but it captures his approach.
The four steps
Choose a concept
Write its name at the top of a blank page. Pick something small and specific, like "inflation" or "how a vaccine works", not "economics" or "biology".
Explain it in simple words
Write or say an explanation as if teaching a 12-year-old. Avoid jargon. Use everyday examples and comparisons.
Find the gaps
Notice where you hesitate, repeat yourself, or fall back on technical words. Those spots show what you do not truly understand.
Go back, learn, and simplify
Return to your book or notes, study the weak parts, and rewrite your explanation more clearly and shortly.
Repeat until you can explain it smoothly, with an example, without looking at your notes.
An example: "How do vaccines work?"
- First attempt: "They stimulate an adaptive immune response through antigens." (Jargon, no real understanding.)
- Gap found: What exactly is an antigen? What is memory?
- After studying: "A vaccine shows your body a harmless piece of a germ. Your body practises making antibodies to fight it, and remembers how. When the real germ arrives, it responds fast."
Ways to use it
- Teach someone. A friend, a sibling, or even a pet. Real questions expose real gaps.
- Record yourself explaining, then listen back.
- Write a short blog post or note in plain language.
- Draw it. Diagrams force you to think about relationships.
When it works best
- Concepts and processes, such as science, maths, economics, and law.
- Preparing for exams and interviews.
- Learning a new skill at work.
What most people miss
- Analogies are powerful. Linking a new idea to something familiar makes it stick.
- Simple does not mean shallow. The aim is clarity, not dumbing down.
- Be honest with yourself. The technique only works if you admit where you are guessing.
