We often don’t understand things as well as we think we do. How often have you “learned” something you can’t fully recall later, or that you can’t explain to someone else? While we’ve previously suggested that you write down or discuss a detailed version of your understanding, there’s a related and simpler way of filling gaps in your own knowledge: the Feynman technique.
This comes from physicist Richard Feynman’s observation that if you can’t explain a complex concept at a simpler level, you probably don’t understand it well yourself. Or to put it another way: Teaching others can be the best way to learn.
How to learn things with the Feynman method
There’s a four-step method that has been named after Feynman. It goes like this:
- Teach the concept to an imaginary child.
- Identify gaps in your knowledge and go back to your source material to learn what you’re missing.
- Organize your notes into a narrative.
- Now go actually teach it to someone.
Teachers out there will recognize this as roughly the same process as preparing a lecture. You may think you know your subject, but as you think through what you’re about to say, you’ll realize there’s a detail you have to go look up. Or you recognize a place where a student will ask a question, and you’re not entirely sure of the best way to answer the question.
When Richard Feynman made his observation that if you can’t explain something simply you don’t understand it, he was trying to prepare a lecture for college freshmen. People have since extended the idea to being able to explain something to “a five-year-old” or “a smart middle schooler.”
There isn’t a specific age of person you need to aim for. I know plenty of science writers who say they explain a complex topic by imagining they are telling their grandmother about it, or their husband, or their best friend. And it’s worth remembering that the younger the audience, the more you have to simplify.
This can backfire if you end up simplifying so much that you leave out all the important details you want to understand. “The doctor will give you some medicine so you won’t get sick” is an explanation of vaccines that a two-year-old could understand. But if you were speaking instead to a ten-year-old, you would need to say something about how the medicine makes you not get sick. You might also want to include a discussion of effectiveness; vaccines aren’t guarantees against illness.
You can repeat the first and the second steps of the Feynman method over and over, if you like. Explain the subject out loud or in a note on your phone, then brush up on the parts that didn’t come easily, and repeat. The third and fourth steps are only necessary if you want to be able to explain the subject to someone else.
Organizing your notes is important because you need to know where to start. The way we think about a topic is often in a series of nested thoughts (where addressing one thought reminds us to go deeper, like this), but to make a clear explanation, you need to disentangle all those pieces and lay them out into a path that can be followed.
Finally, you can deliver your explanation to that actual child, or grandmother, or partner. And if they ask questions you can’t answer, that doesn’t mean you’ve failed. Just answer with an honest “I don’t know, but I’ll find out,” and run through the steps one more time.