How to be a scientist in the words of Richard Feynman

Richard Phillips Feynman was a great inspiration to me, and I still think gives the most eloquent and concise descriptions of what it means to be a scientist. I recently discovered the wealth of material now available online, particularly on YouTube, and put together this compilation partly for myself and partly for my graduate students.

The first half is short (<10 min) videos and quotations, separated by subject. The second half covers complete lectures and other extended material, such as books.

The Scientific Method

How to avoid fooling yourself

“The first principle is that you must not fool yourself — and you are the easiest person to fool.”

“Cargo Cult Science”


"I think the educational and psychological studies I mentioned are
examples of what I would like to call cargo cult science. In the
South Seas there is a cargo cult of people. During the war they saw
airplanes land with lots of good materials, and they want the same
thing to happen now. So they've arranged to imitate things like
runways, to put fires along the sides of the runways, to make a
wooden hut for a man to sit in, with two wooden pieces on his head
like headphones and bars of bamboo sticking out like antennas--he's
the controller--and they wait for the airplanes to land. They're
doing everything right. The form is perfect. It looks exactly the
way it looked before. But it doesn't work. No airplanes land. So
I call these things cargo cult science, because they follow all the
apparent precepts and forms of scientific investigation, but
they're missing something essential, because the planes don't land."

(Millikan’s Oil Drop Experiment, etc.)

“There is one feature I notice that is generally missing in cargo cult science. … It’s a kind of scientific integrity, a principle of scientific thought that corresponds to a kind of utter honesty — a kind of leaning over backwards. For example, if you’re doing an experiment, you should report everything that you think might make it invalid — not only what you think is right about it; other causes that could possibly explain your results; and things you thought of that you’ve eliminated by some other experiment, and how they worked — to make sure the other fellow can tell they have been eliminated.”

“We’ve learned from experience that the truth will come out. Other experimenters will repeat your experiment and find out whether you were wrong or right. Nature’s phenomena will agree or they’ll disagree with your theory. And, although you may gain some temporary fame and excitement, you will not gain a good reputation as a scientist if you haven’t tried to be very careful in this kind of work. And it’s this type of integrity, this kind of care not to fool yourself, that is missing to a large extent in much of the research in cargo cult science.”


Knowing vs Understanding (1) — Knowing the name of something vs knowing something; Disrespect for Respectable; The Pleasure of Finding Things Out


Knowing vs Understanding (2) — Character of a theory (Equations vs Philosophy Behind Ideas)

Maths and Physics — “Greek vs Babylonian tradition”

Critical Thinking:

It is not unscientific to make a guess, although many people who are not in science think it is. Some years ago I had a conversation with a layman about flying saucers — because I am scientific I know all about flying saucers! I said “I don’t think there are flying saucers”. So my antagonist said, “Is it impossible that there are flying saucers? Can you prove that it’s impossible?” “No”, I said, “I can’t prove it’s impossible. It’s just very unlikely”. At that he said, “You are very unscientific. If you can’t prove it impossible then how can you say that it’s unlikely?” But that is the way that is scientific. It is scientific only to say what is more likely and what less likely, and not to be proving all the time the possible and impossible. To define what I mean, I might have said to him, “Listen, I mean that from my knowledge of the world that I see around me, I think that it is much more likely that the reports of flying saucers are the results of the known irrational characteristics of terrestrial intelligence than of the unknown rational efforts of extra-terrestrial intelligence.” It is just more likely. That is all.”

“The real problem in speech is not precise language. The problem is clear language. The desire is to have the idea clearly communicated to the other person. It is only necessary to be precise when there is some doubt as to the meaning of a phrase, and then the precision should be put in the place where the doubt exists. It is really quite impossible to say anything with absolute precision, unless that thing is so abstracted from the real world as to not represent any real thing.”

“The worthwhile problems are the ones you can really solve or help solve, the ones you can really contribute something to. … No problem is too small or too trivial if we can really do something about it.”

“… Know your place in the world and evaluate yourself fairly, not in terms of the naïve ideals of your own youth, nor in terms of what you erroneously imagine your teacher’s ideals are.”


Longer Stuff



The Character of Physical Law Lectures (The Messenger Lectures)

Pt1: “The Law of Gravitation”

Pt 2: “The Relation of Mathematics to Physics”

Pt 3: “The Great Conservation Principles”

Pt 4: “Symmetry in Physical Law”

Pt 5: “The Distinction of Past and Future”

Pt6: “Probability and Uncertainty”

Pt 7: “Seeking New Laws”


QED: The Sir Douglas Robb Lectures (1979)

Pt 1: “Photons — Corpuscles of Light”

Pt 2: “Fits of Reflection and Transmission — Quantum Behaviour”

[The poor sound quality at the beginning is caused by a problem with Feynman’s microphone, which is replaced after about 17mins]

Pt 3: “Electrons and their Interactions”

Pt 4: “New Queries”