The Feynman Technique: Explaining Simply

We often mistake familiarity for understanding. You read something, it makes sense, and you assume you know it — until you try to explain it and fall apart. The Feynman technique, named after the physicist Richard Feynman, turns simple explanation into a tool for building and testing genuine understanding.

The technique in four steps

The Feynman technique is simple: (1) choose a concept; (2) explain it in plain language, as if to someone with no background; (3) notice where you get stuck, vague, or reach for jargon — those are your gaps; (4) go back to the source, fill the gaps, and simplify again. Repeat until the explanation is clear and honest.

Jargon as a mask

Technical words can hide confusion, even from ourselves. Saying a concept's name is not the same as understanding it. Forcing yourself to explain without jargon strips away that mask and reveals whether real understanding is underneath.

The illusion of explanatory depth

People routinely feel they understand things — how a zipper works, why the seasons change — far better than they do, a well-studied bias called the illusion of explanatory depth. Trying to explain the thing mechanically, step by step, punctures the illusion fast. The Feynman technique weaponises this: it makes the illusion visible so you can fix it.

You think you understand how interest compounds. You try to explain it plainly: "money grows, and then... the growth also grows?" You stumble on why it accelerates. That stumble is the gap. You return to the idea, work out that interest earns interest on interest, and re-explain it cleanly. The failed explanation was not a setback — it was the diagnosis.

Simplifying can be taken too far into distortion. "Explain it simply" does not mean "make it wrong" — a simple explanation must still be accurate. The skill is to reduce complexity without breaking truth. An explanation that is clear but false has failed differently than one that is accurate but muddled; the goal is clear and correct.

Richard Feynman, a Nobel Prize-winning physicist, was legendary as a teacher precisely because he insisted on explaining difficult ideas in plain, vivid language. A famous story (recounted in accounts of his life) has him unable to prepare a simple lecture on a specialised topic and concluding, tellingly, "I couldn't reduce it to the freshman level. That means we really don't understand it." For Feynman, the ability to explain something simply was the test of whether it was truly understood — by anyone. Whether or not every anecdote is exact, the principle he embodied is well founded and matches the research on the illusion of explanatory depth: if you cannot explain it plainly and correctly, you do not yet fully understand it. That is the enduring lesson of the technique that bears his name.

• "If it made sense when I read it, I understand it." Recognition is not the same as being able to explain.
• "Using the right technical terms proves understanding." Jargon can mask confusion.
• "Simple means dumbed-down and inaccurate." A good simple explanation stays true.
• "Getting stuck explaining means you failed." The stuck point is the exact gap to fix.

Take something you believe you understand. Write a plain-language explanation aimed at a curious twelve-year-old, using no jargon. Mark every place you hesitate — then go learn those parts.

Think Like a Maester: If you cannot explain it simply and truthfully, you have found the edge of your understanding — which is exactly where to learn next.

1. What are the four steps of the Feynman technique?
2. How can jargon mask a lack of understanding?
3. What is the illusion of explanatory depth?
4. Why must a simple explanation still be accurate?
5. What did Feynman mean by not being able to reduce a topic to the freshman level?

The Feynman technique tests and builds understanding by forcing you to explain a concept in plain language, spot where you get stuck or hide behind jargon, fill those gaps, and simplify again. It exploits the illusion of explanatory depth — our tendency to overrate our understanding — by making gaps visible. As Feynman held, if you cannot explain something simply and accurately, you do not yet truly understand it; the failed explanation is the diagnosis that shows you where to learn.

• Familiarity Is Not Mastery
• Becoming a Mentor or Tutor