A Brief Introduction to Richard Feynman.

from a review of Feynman's biography at http://www.edu-observatory.org/eo/bkr/bkr.93.06 :

Richard P. Feynman was (and is) a hero to me, as he was (and is) to
physics students and colleagues around the world. When he died on
February 15th, 1988, the world lost one of the finest theoretical
physicist and one of the finest teachers of the 20th century.
Hans Bethe of Cornell University, paraphrasing the mathematician Mark
Kac, said there are two kinds of geniuses. The ordinary kind does great
things but lets other scientists feel that they could do the same if
only they worked hard enough. The other kind performs magic. "A magician
does things that nobody else can do and that seem completely
unexpected," Dr. Bethe said, "and that's Feynman."

To his scientific colleagues, Richard Feynman was a magician of the
highest caliber. Architect of quantum theories, 'enfant terrible' of the
atomic bomb project, caustic critic of the space shuttle commission,
Nobel Prize winner for work that gave physicists a new and easier way of
describing and calculating the interactions of subatomic particles,
Richard Feynman left his mark on virtually every area of modern physics.
Originality was his obsession. Never content with what he knew or with
what others knew, Feynman ceaselessly questioned scientific truths. But
there was another side to him, one which made him a legendary figure
among scientists. His curiosity moved well beyond things scientific: he
taught himself how to play drums, to give massages, to write Chinese, to
crack safes.

Feynman, Richard P. (1988),  The Value of Science, from the (highly recommended) Classic Feynman: All the Adventures of a Curious Character.

First, the 1988 Introduction by Feynman himself (he died one month later):

    When I was younger, I thought science would make good things for everybody. It was obviously useful; it was good. During the war I worked on the atomic bomb. This result of science was obviously a very serious matter: It represented the destruction of people.

After the war I was very worried about the bomb. I didn't know what the future was going to look like, and I certainly wasn't anywhere near sure that we would last until now. Therefore one question was: is there some evil involved in science?

Put another way, what is the value of the science I had dedicated myself to—the thing I loved—when I saw what terrible things it could do? It was a question I had to answer.

"The Value of Science" was a kind of report, if you will [Feynman gave that "report" as a public address to a 1955 meeting of the National Academy of Sciences.] on many of the thoughts that came to me when I tried to answer that question.

Richard Feynman, January 1988

Then the lecture itself:

The Value of Science

     From time to time people suggest to me that scientists ought to give more consideration to social problems - especially that they should be more responsible in considering the impact of science on society.  It seems to be generally believed that if the scientists would only look at these very difficult social problems and not spend so much time fooling with less vital scientific ones, great success would come of it.
     It seems to me that we do think about these problems from time to time, but we don't put a full-time effort into them - the reasons being that we know we don't have any magic formula for solving social problems, that social problems are very much harder than scientific ones, and that we usually don't get anywhere when we do think about them.
     I believe that a scientist looking at nonscientific problems is just as dumb as the next guy - and when he talks about a nonscientific matter, he sounds as naive as anyone untrained in the matter.  Since the question of the value of science is not a scientific subject, this talk is dedicated to proving my point - by example.
     The first way in which science is of value is familiar to everyone.  It is that scientific knowledge enables us to do all kinds of things and to make all kinds of things.  Of course if we make good things, it is not only to the credit of science; it is also to the credit of the moral choice which led us to good work.  Scientific knowledge is an enabling power to do either good or bad - but it does not carry instructions on how to use it.  Such power has evident value - even though the power may be negated by what one does with it.
     I learned a way of expressing this common human problem on a trip to Honolulu.  In a Buddhist temple there, the man in charge explained a little bit about the Buddhist religion for tourists, and then ended his talk by telling them he had something to say to them that they would never forget - and I have never forgotten it.  It was a proverb of the Buddhist religion:
To every man is given the key to the gates of heaven; the same key opens the gates of hell.
     What then, is the value of the key to heaven?  It is true that if we lack clear instructions that enable us to determine which is the gate to heaven and which the gate to hell, the key may be a dangerous object to use.
     But the key obviously has value: how can we enter heaven without it?
     Instructions would be of no value without the key.  So it is evident that, in spite of the fact that it could produce enormous horror in the world, science is of value because it can produce something.
     Another value of science is the fun called intellectual enjoyment which some people get from reading and learning and thinking about it, and which others get from working in it.  This is an important point, one which is not considered enough by those who tell us it is our social responsibility to reflect on the impact of science on society.
     Is this mere personal enjoyment of value to society as a whole? No! But it is also a responsibility to consider the aim of society itself.  Is it to arrange matters so that people can enjoy things?  If so, then the enjoyment of science is as important as anything else.
     But I would like not to underestimate the value of the world view which is the results of scientific effort.  We have been led to imagine all sorts of things infinitely more marvelous than the imaginings of poets and dreamers of the past.  It shows that the imagination of nature is far, far greater than the imagination of man.  For instance, how much more remarkable it is for us all to be stuck - half of us upside down - by a mysterious attraction to a spinning ball that has been swinging in space for billions of years than to be carried on the back of an elephant supported on a tortoise swimming in a bottomless sea.
     I have thought about these things so many times alone that I hope you will excuse me if I remind you of this type of thought that I am sure many of you have had, which no one could ever have had in the past because people then didn't have the information we have about the world today.
There are the rushing waves
mountains of molecules
each stupidly minding its own business
trillions apart
yet forming white surf in unison.

Ages on ages
before any eyes could see
year after year
thunderously pounding the shore as now.
For whom, for what?
On a dead planet
with no life to entertain.

Never at rest
tortured by energy
wasted prodigiously by the sun
poured into space
A mite makes the sea roar.

Deep in the sea
all molecules repeat
the patterns of one another
till complex new ones are formed.
They make others like themselves
and a new dance starts.

Growing in size and complexity
living things
masses of atoms
DNA, protein
dancing a pattern ever more intricate.

Out of the cradle
onto dry land
here it is
atoms with consciousness;
matter with curiosity.

Stands at the sea,
wonders at wondering: I
a universe of atoms
an atom in the universe.

     The same thrill, the same awe and mystery, comes again and again when we look at any question deeply enough.  With more knowledge comes a deeper, more wonderful mystery, luring one on to penetrate deeper still.  Never concerned that the answer may prove disappointing, with pleasure and confidence we turn over each new stone to find unimagined strangeness leading on to more wonderful questions and mysteries - certainly a grand adventure!
     It is true that few unscientific people have this particular type of religious experience.  Our poets do not write about it; our artists do not try to portray this remarkable thing.  I don't know why.  Is no one inspired by our present picture of the universe?  This value of science remains unsung by singers: you are reduced to hearing not a song or poem, but an evening lecture about it.  This is not yet a scientific age.
     Perhaps one of the reasons for this silence is that you have to know how to read the music.  For instance, the scientific article may say, "The radioactive phosphorus content of the cerebrum of the rat decreases to one-half in a period of two weeks."  Now what does that mean?
     It means that phosphorous that is in the brain of a rat - and also in mine, and yours - is not the same phosphorus as it was two weeks ago.  It means the atoms that are in the brain are being replaced: the ones that were there before have gone away.
     So what is this mind of ours: what are these atoms with consciousness?  Last week's potatoes!  They now can remember what was going on in my mind a year ago - a mind which has long ago been replaced.
     To note that the thing I call my individuality is only a pattern or dance, that is what it means when one discovers how long it takes for the atoms of the brain to be replaced by other atoms.  The atoms come into my brain, dance a dance, and then go out - there are always new atoms, but always doing the same dance, remembering what the dance was yesterday.
     When we read about this in the newspaper, it says "Scientists say this discovery may have importance in the search for a cure for cancer."  The paper is only interested in the use of the idea, not the idea itself.  Hardly anyone can understand the importance of an idea, it is so remarkable.  Except that, possibly, some children catch on.  And when a child catches on to an idea like that, we have a scientist.  It is too late1 for them to get the spirit when they are in our universities, so we must attempt to explain these ideas to children.
     I would now like to turn to a third value that science has.  It is a little less direct, but not much.  The scientist has a lot of experience with ignorance and doubt and uncertainty, and this experience is of very great importance, I think.  When a scientist doesn't know the answer to a problem, he is ignorant.  When he has a hunch as to what the result is, he is uncertain.  And when he is pretty darn sure of what the result is going to be, he is still in some doubt.  We have found it of paramount importance that in order to progress we must recognize our ignorance and leave room for doubt.  Scientific knowledge is a body of statements of varying degrees of certainty - some most unsure, some nearly sure, but none absolutely certain.
     Now, we scientists are used to this, and we take it for granted that it is perfectly consistent to be unsure, that it is possible to live and not know.  But I don't know whether everyone realizes this is true.  Our freedom to doubt was born out of a struggle against authority in the early days of science.  It was a very deep and strong struggle: permit us to question - to doubt - to not be sure.  I think that it is important that we do not forget this struggle and thus perhaps lose what we have gained.  Herein lies a responsibility to society.
     We are all sad when we think of the wondrous potentialities human beings seem to have, as contrasted with their small accomplishments.  Again and again people have thought that we could do much better.  Those of the past saw in the nightmare of their times a dream for the future.  We, of their future, see that their dreams, in certain ways surpassed, have in many ways remained dreams.  The hopes for the future today are, in good share, those of yesterday.
     It was once thought that the possibilities people had were not developed because most of the people were ignorant.  With universal education, could all men be Voltaires? Bad can be taught at least as efficiently as good.  Education is a strong force, but for either good or evil.
     Communications between nations must promote understanding - so went another dream.  But the machines of communication can be manipulated.  What is communicated can be truth or lie.  Communication is a strong force, but also for either good or evil.
     The applied sciences should free men of material problems at least.  Medicine controls diseases.  And the record here seems all to the good.  Yet there are some patiently working today to create great plagues and poisons for use in warfare tomorrow.
     Nearly everyone dislikes war.  Our dream today is peace.  In peace, man can develop best the enormous possibilities he seems to have.  But maybe future men will find that peace, too, can be good and bad.  Perhaps peaceful men will drink out of boredom.  Then perhaps drink will become the great problem which seems to keep man from getting all he thinks he should out of his abilities.
     Clearly, peace is a great force - as are sobriety, material power, communication, education, honesty, and the ideals of many dreamers.  We have more of these forces to control than did the ancients.  And maybe we are doing a little better than most of them could do.  But what we ought to be able to do seems gigantic compared with our confused accomplishments.
     Why is this?  Why can't we conquer ourselves?
     Because we find that even great forces and abilities do not seem to carry with them clear instructions on how to use them.  As an example, the great accumulation of understanding as to how the physical world behaves only convinces one that this behavior seems to have a kind of meaninglessness.  The sciences do not directly teach good and bad.
     Through all ages of our past, people have tried to fathom the meaning of life.  They have realized that if some direction or meaning could be given to our actions, great human forces would be unleashed.  So very many answers have been given to the question of the meaning of it all.  But the answers have been of all different sorts, and the proponents of one answer have looked with horror at the actions of the believers in another - horror, because from a disagreeing point of view all the great potentialities of the race are channeled into a false and confining blind alley.  In fact, it is from the history of the enormous monstrosities created by false belief that philosophers have realized the apparently infinite and wondrous capacities of human beings.  The dream is to find the open channel.
     What, then, is the meaning of it all?  What can we say to dispel the mystery of existence?
     If we take everything into account - not only what the ancients knew, but all of what we know today that they didn't know - then I think we must frankly admit that we do not know.
     But, in admitting this, we have probably found the open channel.
     This is not a new idea; this is the idea of the age of reason.  This is the philosophy that guided the men who made the democracy that we live under.  The idea that no one really knew how to run a government led to the idea that we should arrange a system by which new ideas could be developed, tried out, and tossed out if necessary, with more new ideas brought in - a trial-and-error system.  This method was a result of the fact that science was already showing itself to be a successful venture at the end of the eighteenth century.  Even then it was clear to socially minded people that the openness of possibilities was an opportunity, and that doubt and discussion were essential to progress into the unknown.  If we want to solve a problem that we have never solved before, we must leave the door to the unknown ajar.
     We are at the very beginning of time for the human race.  It is not unreasonable that we grapple with problems.  But there are tens of thousands of years in the future.  Our responsibility is to do what we can, learn what we can, improve the solutions, and pass them on.  It is our responsibility to leave the people of the future a free hand.  In the impetuous youth of humanity, we can make grave errors that can stunt our growth for a long time.  This we will do if we say we have the answers now, so young and ignorant as we are.  If we suppress all discussion, all criticism, proclaiming "This is the answer, my friends; man is saved!" we will doom humanity for a long time to the chains of authority, confined to the limits of our present imagination.  It has been done so many times before.
     It is our responsibility as scientists, knowing the great progress which comes from a satisfactory philosophy of ignorance, the great progress which is the fruit of freedom of thought, to proclaim the value of this freedom; to teach how doubt is not to be feared but welcomed and discussed; and to demand this freedom as our duty to all coming generations.