domingo, 17 de noviembre de 2019

The Feynman Technique

When I first read about Feynman, I was inspired to try to formulate many of these
different observations into a concrete method I could apply to my own studies. What
resulted was something I named the Feynman Technique and applied extensively during
my MIT Challenge. The purpose of using this technique is to help develop intuition about
the ideas you are learning. It can be used when you don’t understand an idea at all or
simply when you understand something a little but really want to turn it into a deep
The method is quite simple:
Write down the concept or problem you want to understand at the top of a piece of
In the space below, explain the idea as if you had to teach it to someone else.
If it’s a concept, ask yourself how you would convey the idea to someone who
has never heard of it before.
If it’s a problem, explain how to solve it and—crucially—why that solution
procedure makes sense to you.
When you get stuck, meaning your understanding fails to provide a clear answer, go
back to your book, notes, teacher, or reference material to find the answer.
The crux of this method is that it tries to dispel the illusion of explanatory depth. Since
many of our understandings are never articulated, it’s easy to think you understand
something you don’t. The Feynman Technique bypasses this problem by forcing you to
articulate the idea you want to understand in detail. Just as drawing a bicycle quickly
confirms whether you have a basic grasp of how it is put together, using this technique
will quickly reveal how much you really understand of your subject. Now any gaps in your
understanding will become obvious as you struggle to explain key parts of the idea.
The technique itself has some nuances and can be applied in a few different ways that
might be helpful, depending on your specific intuitive deficit.
Application 1: For Things You Don’t Understand at All
The first way to use this approach is when you don’t understand something at all. In this
case, the easiest way is to do it with the book in hand and go back and forth between
your explanation and the one in the book. This lacks the benefits of retrieval practice, but
it can often be essential when the explanation you’ve been given baffles you. Feynman
himself did something similar when presented with what he saw to be philosophical
I had this uneasy feeling of “I’m not adequate,” until finally I said to myself, “I’m going
to stop, and read one sentence slowly, so I can figure out what the hell it means.”
So I stopped—at random—and read the next sentence very carefully. I can’t remember
it precisely, but it was very close to this: “The individual member of the social
community often receives his information via visual, symbolic channels.” I went back
and forth over it, and translated. You know what it means? “People read.” 17
Although Feynman’s method was aimed more at illustrating the deliberately confusingnature of the prose rather than trying to understand a nuanced meaning, the same
method can help whenever you’re learning anything that goes over your head.
I used this technique when taking a class on machine vision during the MIT Challenge. I
didn’t understand photogrammetry, a technique of determining the 3D shape of an object
based on a series of 2D pictures taken under different lighting conditions. It involved
some tricky concepts, so I wasn’t quite sure how it worked. With my textbook at my side, I
wrote a few pages of notes, trying to sketch out the broad strokes of the idea so I could
get the general gist of it. 18
Application 2: For Problems You Can’t Seem to Solve
A second way to apply this is for solving a difficult problem or mastering a technique. In
this instance, it’s very important to go through the problem step by step alongside the
explanation you generate, rather than simply summarizing it. Summarizing may end up
skipping over the core difficulties of the problem. Going deeper may take time, but it can
help you get a strong grasp over a new method in one go, rather than needing numerous
repetitions to memorize the steps.
I applied this to a class in computer graphics for a technique I was struggling with called
grid acceleration. This is a method of speeding up the performance of ray-traced
rendering systems by avoiding analyzing objects that “obviously” won’t be on the part of
the screen you’re drawing. To get a better handle on this, I walked through the problem
with the technique, drawing a little snowman that I imagined rendering, with lines
shooting out of an eyeball representing the camera. 19
Application 3: For Expanding Your Intuition
A final way to apply this method is to ideas that are so important that it would really help
if you had a great intuition about them. In this application of the method, instead of
focusing on explaining every detail or going along with the source material, you should try
to focus on generating illustrative examples, analogies, or visualizations that would make
the idea comprehensible to someone who has learned far less than you have. Imagine
that instead of trying to teach the idea, you are being paid to write a magazine article
explaining the idea. What visual intuitions would you use to pin down the abstractions?
Which examples would flesh out a general principle? How could you make something
confusing feel obvious?
I applied this to understanding the concept of voltage in an early class on
electromagnetism during the MIT Challenge. Though I was comfortable using the concept
in problems, I didn’t feel that I had a good intuition of what it was. It’s obviously not
energy, electrons, or flows of things. Still, it was hard to get a mental image of an abstract
concept on a wire. Going through this technique and comparing the equations to the ones
for gravity, it’s clear that voltage is to the electrical force as height is to the gravitational
force. Now I could form a visual image. The wires were like troughs of water at different
heights. Batteries were like pumps, moving the water up. Resistors were like hoses
dropping down, of various widths to impede the flow of water draining down. Although this
picture of troughs and hoses wasn’t necessary for solving the equations, it stuck with me
and helped me reason my way out of new situations more easily than if voltage had just
been an abstract quantity.Demystifying Intuition
When many people look at a genius like Richard Feynman, they’re inclined to focus on his
seemingly effortless intuitive leaps. In his playful style and rebellious impulses, he may
seem to defy the stereotype that learning requires hard work. However, as we go beneath
the surface, it becomes clear that he shared much in common with the other ultralearners
I’ve studied. He worked hard on understanding things, and he put incredible amounts of
his spare time into mastering the methods that made his intuition work. In his early days
in college, he and a friend went back and forth over the early books on quantum
mechanics, racing ahead of their classmates to understand it. He even made a meticulous
timetable to allocate hours to his many intellectual pursuits. Even in his trivial obsessions,
he displayed a streak for aggressive methods; while learning lock picking, for example, he
trained himself to go through all the possible combinations, practicing them repeatedly: “I
got it down to an absolute rhythm so I could try the 400 possible back numbers in less
than half an hour. That meant I could open a safe in a maximum of eight hours—with an
average time of four hours.” 20
When people hear about geniuses, especially the iconoclastic ones such as Feynman,
there’s a tendency to focus on their gifts and not their efforts. I have no doubt that
Feynman possessed gifts. But perhaps his greatest one was his ability to merge tenacious
practice and play. He approached picking locks with the same enthusiasm for solving
puzzles that he did for unraveling the secrets of quantum electrodynamics. It’s this spirit
of playful exploration that I want to turn to in the final principle of ultralearning: