Quotations are indexed alphabetically by their author. For authors with multiple quotations, the quotations are alphabetized by the first word in the quotations.
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Programs must be written for people to read, and only incidentally for
machines to execute.
- H. Abelson and G. Sussman (in "The Structure and Interpretation of Computer Programs) |
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The computer revolution is a revolution in the way we think and in the way we
express what we think.
The essence of this change is the emergence of what might best be called
procedural epistemology--the study of the structure of knowledge from an
imperative point of view, as opposed to the more declarative point of view
taken by classical mathematical subjects.
- H. Abelson and G. Sussman (in "The Structure and Interpretation of Computer Programs) |
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We have also obtained a glimpse of another crucial idea about languages and
program design.
This is the approach of statified design, the notion that a complex system
should be structured as a sequence of levels that are described using a
sequence of languages.
Each level is constructed by combining parts that are regarded as primitive
at that level, and the parts constructed at each level are used as primitives
at the next level.
The language used at each level of a stratified design has primitives, means
of combination, and means of abstraction appropriate to that level of detail.
- H. Abelson and G. Sussman (in "The Structure and Interpretation of Computer Programs) |
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A common mistake people make when trying to design something completely foolproof is
to underestimate the ingenuity of complete fools.
- D. Adams |
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Good teaching is more a giving of the right questions than a giving of the
right answers.
- J. Albers |
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They know enough who know how to learn
- J. Adams |
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Computer Science is a science of abstraction -creating the right
model for a problem and devising the appropriate mechanizable
techniques to solve it.
- A. Aho and J. Ullman |
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Each pattern describes a problem which occurs over and over again in our
environment, and then describes the core of the solution to that problem,
in such a way that you can use this solution a million times over, without
ever doing it in the same way twice.
- C. Alexander |
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Don't worry about people stealing your ideas.
If your ideas are any good, you'll have to ram them down people's throats.
- H. Aiken |
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Eighty percent of success is showing up.
- W. Allen |
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If you're not failing every now and again, it's a sign you're not doing
anything very innovative.
- W. Allen |
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More is different.
- P. Anderson (attacking the reductionist hypothesis in science, by concluding that quantitatively larger systems can be qualitatively different) |
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Today, most software exists, not to solve a problem, but to interface with
other software.
- I. O. Angell |
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All programmers are playwrights and all computers are lousy actors.
- Anonymous |
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Any programming problem can be solved by adding a level of indirection.
(also see "Any performance problem..." by M. Haertel).
- Anonymous |
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Bad code isn't bad, its just misunderstood.
- Anonymous |
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Debugging is anticipated with distaste, performed with reluctance,
and bragged about forever.
- Anonymous |
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Experience is a poor teacher: it gives its tests before it teaches its lessons.
- Anonymous |
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If I had eight hours to chop down a tree, I would spend 6 hours sharpening an
axe.
- Anonymous |
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If you understand what you're doing, you're not learning anything.
- Anonymous |
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In theory, there is no difference between theory and practice, but not in
practice.
- Anonymous |
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It is easier to measure something than to understand what you have measured.
- Anonymous |
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Measure twice, cut once.
- Anonymous |
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Microsoft, where quality is job 1.1
- Anonymous |
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On a visit to the NASA space center, President Kennedy spoke to a man
sweeping up in one of the buildings.
"What's your job here?" asked Kennedy.
"Well Mr. President," the janitor replied,
"I'm helping to put a man on the moon".
- Anonymous |
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One day a mother comes home from work and asks her son, "What did you do
today?"

The mother, incredulous, asked, "Our dog can play the piano?",
to which the son laughed and replied, "Of course not mom.
I said that I taught him; I didn't say that he learned how."
- Anonymous |
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Programming languages should be designed not by piling feature on top of
feature, but by removing the weaknesses and restrictions that make additional
features appear necessary.
- Anonymous, Revised Report on the Algorithmic Language Scheme |
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Programs for sale: Fast, Reliable, Cheap: choose two.
- Anonymous |
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Ready, fire, aim (the fast approach to software development). Ready, aim, aim, aim, aim ... (the slow approach to software development). - Anonymous |
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Real programmers don't comment their code.
If it was hard to write, it should be hard to understand.
- Anonymous |
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Recurses! Called again.
- Anonymous |
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The huge printing presses of a major Chicago newspaper began malfunctioning on
the Saturday before Christmas, putting all the revenue for advertising
that was to appear in the Sunday paper in jeopardy.
None of the technicians could track down the problem.
Finally, a frantic call was made to the retired printer who had worked
with these presses for over 40 years.
"We'll pay anything; just come in and fix them," he was told.
When he arrived, he walked around for a few minutes, surveying the presses; then he approached one of the control panels and opened it. He removed a dime from his pocket, turned a screw 1/4 of a turn, and said, "The presses will now work correctly." After being profusely thanked, he was told to submit a bill for his work. The bill arrived a few days later, for $10,000.00! Not wanting to pay such a huge amount for so little work, the printer was told to please itemize his charges, with the hope that he would reduce the amount once he had to identify his services. The revised bill arrived: $1.00 for turning the screw; $9,999.00 for knowing which screw to turn. Commentary: most debugging problems are fixed easily; identifying the location of the problem is hard. - Anonymous |
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The person who knows HOW will always have a job.
The person who knows WHY will always be his/her boss.
- Anonymous |
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The sooner you get behind in your work, the more time you have to catch up.
- Anonymous |
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There are only 10 different kinds of people in the world: those who know binary
and those who don't.
- Anonymous |
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Think (design) globally; act (code) locally.
- Anonymous |
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Think twice, code once.
- Anonymous |
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Time is an excellent teacher; but eventually it kills all its students.
- Anonymous |
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Weeks of programming can save you hours of planning.
- Anonymous |
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When a programming language is created that allows programmers to program
in simple English, it will be discovered that programmers cannot speak
English.
- Anonymous |
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Why do we never have time to do it right, but always have time to do it over?
- Anonymous |
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By viewing the old we learn the new.
- Anonymous Chinese Proverb |
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Give me a fish and I eat for a day. Teach me to fish and I eat for a lifetime.
- Anonymous Chinese Proverb |
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He who asks is a fool for five minutes; he who does not ask remains a fool
forever.
- Anonymous Chinese Proverb |
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Teachers open the door, but you must enter by yourself.
- Anonymous Chinese Proverb |
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Tell me and I forget. Show me and I remember. Involve me and I understand.
- Anonymous Chinese Proverb |
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The first step towards wisdom is calling things by their right names.
- Anonymous Chinese Proverb |
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The person who says it cannot be done should not interrupt the person doing it.
- Anonymous Chinese Proverb |
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He who is ashamed of asking is ashamed of learning.
- Anonymous Danish Proverb |
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No matter how far down the wrong road you have gone, turn back now.
- Anonymous Turkish Proverb |
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Those who know, do. Those who understand, teach.
- Aristotle |
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We are what we repeatedly do.
Excellence, then, is not an act, but a habit.
- Aristotle |
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The most exciting phrase to hear in science -the one that heralds new
discoveries- is not "Eureka!" but "That's funny...".
- I. Asimov |
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The Analytical Engine weaves Algebraical patterns just as the Jacquard loom
weaves flowers and leaves.
- A. Augusta, Countess of Lovelace, on Babbage's Analytical Engine |
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On two occasions, I have been asked [by members of Parliament], "Pray,
Mr. Babbage, if you put into the machine wrong figures, will the right
answers come out?"
I am not able to rightly apprehend the kind of confusion of ideas that
could provoke such a question.
- C. Babage |
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I, myself, have had many failures and I've learned that if you are not
failing a lot, you are probably not being as creative as you could be
-you aren't stretching your imagination.
- J. Backus |
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A prudent question is one-half of wisdom.
- F. Bacon |
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I can only think that the book is read because it deals with the
difficulties of schooling, which do not change.
Please note: the difficulties, not the problems.
Problems are solved or disappear with the revolving times.
Difficulities remain.
It will always be difficult to teach well, to learn accurately; to read,
write, and count readily and competently; to acquire a sense of history
and start one's education or anothers.
- J. Barzun ("Begin Here", pp 14), |
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The American university is built on two false premises: that all teachers must
add to the existing stock of knowledge by research, and that all
self-respecting institutions fulfill this role only by employing productive
scholars...Of course, the teacher must keep reading and thinking abreast of
his time, but this does not mean that he must write and publish.
The confusion hides a further absurd assumption, which is that when a man
writes a scholarly book that reaches a dozen specialists he adds immeasurably
to the world's knowledge; whereas if he imparts his thoughts and his reading
to one hundred and fifty students every year, he is wasting his time and
leaving the world in darkness.
One is tempted to ask what blinkered pedant ever launched the notion that
students in coming to college seceded from the human race and may therefore
be safely left out when knowledge is being broadcast.
- J. Barzun ("Teacher in America"), |
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The sole justification of teaching, of the school itself, is that the
student comes out of it able to do something he could not do before.
I say do and not know, because knowledge that doesn't
lead to doing something new or doing something better is not knowledge
at all.
- J. Barzun ("Begin Here", pp 112), |
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The truth is, when all is said and done, one does not teach a subject,
one teaches a student how to learn it.
Teaching may look like administering a dose, but even a dose must be worked
on by the body if it is to cure.
Each individual must cure his or her own ignorance.
- J. Barzun ("Begin Here", pp 35), |
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Optimism is an occupational hazard of programming: testing is the treatment.
- K. Beck |
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The cheapest, fastest, and most reliable components of a computer system are
those that aren't there.
- G. Bell |
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Dakin (to Irwin, his teacher):
Do you really believe that, sir, or are you just trying to make us think?
- A. Bennet (in "The History Boys") |
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The key to performance is elegance, not batallions of special cases.
- J. Bently & D. McIlroy |
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Walking on water and developing software from a specification are easy if both
are frozen.
- E. Berard |
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More than the act of testing, the act of designing tests is one of the best bug
preventers known.
The thinking that must be done to create a useful test can discover and
eliminate bugs before they are coded - indeed, test-design thinking can
discover and eliminate bugs at every stage in the creation of software, from
conception to specification, to design, coding and the rest.
- B. Bezier |
Percy: You know, they do say that the Infanta's eyes are more beautiful than the famous Stone of Galveston. Edmund: Mm! ... What? Percy: The famous Stone of Galveston, My Lord. Edmund: And what's that, exactly? Percy: Well, it's a famous blue stone, and it comes ... from Galveston. Edmund: I see. And what about it? Percy: Well, My Lord, the Infanta's eyes are bluer than it, for a start. Edmund: I see. And have you ever seen this stone? Percy: (nods) No, not as such, My Lord, but I know a couple of people who have, and they say it's very very blue indeed. Edmund: And have these people seen the Infanta's eyes? Percy: No, I shouldn't think so, My Lord. Edmund: And neither have you, presumably. Percy: No, My Lord. Edmund: So, what you're telling me, Percy, is that something you have never seen is slightly less blue than something else you have never seen. Percy: (finally begins to grasp) Yes, My Lord.I sometimes feel this way when trying to explain a new programming concept. - From the Queen of Spain's Beard episode of
Blackadder. |
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There is a division in the student population between those who go to college
to learn and those who go to college to earn a diploma.
- J. Blau (letter to the editor, Chronicle of Higher Education, May 24, 2002) |
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It is wrong to think that the task of physics is to find out how nature is.
Physics concerns what we say about nature.
- N. Bohr |
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Opposites are not contradictory but complementary.
- N. Bohr |
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Software development has been, is, and will likely remain fundamentally hard.
Building quality systems involves an essential and irreducible complexity,
which is why the entire history of software engineering can be characterized
as one of rising levels of abstraction.
As such, the task of the software development team is to engineer the illusion
of simplicity.
Nonetheless, software-intensive systems can amplify human intelligence, but
they cannot replace human judgment; software-intensive systems can fuse,
co-ordinate, classify, and analyze information, but they cannot create
knowledge.
In other words, not everything we want to build can be built: there exist
pragmatic theoretical and technical limits that make software develpment
hard if not impossible.
Furthermore, not everything we want to build should be built: there exist
moral economic, social, and political limits that govern human industry.
From fundamental to human, these are the factors tht define the limits of
software, factors that separate our vision from execution.
- G. Booch (in a blurb from a talk, "The Limits of Software") |
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That language is an instrument of human reason, and not merely a medium
for the expression of thought, is a truth generally admitted.
- G. Boole |
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The greatest obstacle to discovery is not ignorance, but the illusion of
knowledge.
- D. Boorstin |
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The most likely way for the world to be destroyed, most experts agree, is by
accident.
That's where we come in; we're computer professionals.
We cause accidents.
- N. Borenstein |
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All models are wrong; some models are useful.
- G. Box |
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Simplicity and flexibility will trump optimization and power in a world where
connectivity is the key.
- A. Bosworth (paraphrased by David Bank in Breaking Windows, page 203) |
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The important thing in science is not so much to obtain new facts as to
discover new ways of think about them.
- W. Bragg |
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Information wants too be free.
Information also wants to be expensive.
Information wants to be free because it has become so cheap to distribute,
copy, and recombine---too cheap to meter.
It wants to be expensive because it can be immeasurably valuable to the
recipient.
That tension will not go away.
It leads to endless wrenching debate about price, copyright, "intellectual
property", the moral rightness of casual distribution, because each round
of new devices makes the tension worse, not better.
- S. Brand (see the Information Wants to Be Free web page) |
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It is important that students bring a certain ragamuffin, barefoot irreverence
to their studies; they are not here to worship what is known, but to
question it.
- J. Bronowski |
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That is the essence of science: ask an impertinent question, and you are on
the way to a pertinent answer.
- J. Bronowski |
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Welcome to Yale.
Yale will be for you and to you what you make of it.
Despite the gloom of the times this is not a gloomy place.
It is a place where life can have purpose without being a society of driven
men and women.
It is also a place where there is no escape from argument, for the next person
you meet will not be likely to agree with the last person talked to.
This is a community which rewards participation but does not expect conformity.
This is primarily a place for learning, but not all learning is in books or
laboratories or classrooms.
You probably have not been as free before.
You may not be as free again.
Enjoy the privilege of doubt.
Make the most of it.
- K. Brewster |
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Good judgment comes from experience; experience comes from bad judgment.
- F. Brooks |
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Plan to throw one away; you will anyhow.
- F. Brooks ("The Mythical Man-Month", Chapter 11) |
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If you plan to throw one away, you will throw away two.
- C. Zerouni |
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Scientists build to learn; Engineers learn to build.
- F. Brooks |
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The hardest part of the software task is arriving at a complete and consistent
specification, and much of the essence of building a program is in fact the
debugging of the specification.
- F. Brooks |
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The programmer, like the poet, works only slightly removed from pure
thought-stuff.
He builds castles in the air, from air, creating by exertion of the
imagination.
Few media of creation are so flexible, so easy to polish and rework, so readily
capable of realizing grand conceptual structures.
Yet the program construct, unlike the poet's words, is real in
the sense that it moves and works, producing visible outputs separate from
the construct itself.
It prints results, draws pictures, produces sounds, moves arms.
The magic of myth and legend has come true in our time.
One types the correct incantation on a keyboard, and a display screen comes to
life, showing things that never were nor could be.
...
The computer resembles the magic of legend in this respect, too.
If one character, one pause, of the incantation is not strictly in proper form,
the magic doesn't work.
Human beings are not accustomed to being perfect, and few areas of human
activity demand it.
Adjusting to the requirement for perfection is, I think, the most difficult
part of learning to program.
- F. Brooks ("The Mythical Man Month", pages 7-8) |
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Successful software always gets changed.
- F. Brooks |
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A man's reach should exceed his grasp, or what's heaven for?
- R. Browning |
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They may forget what you said, but they will never forget how you made them
feel.
- C.
They are, in short, a perfect match.
- B. Bryson |
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Learning how to learn is life's most important skill.
- T. Buzan |
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The first 90% of the code accounts for the first 90% of the development time.
The remaining 10% of the code accounts for the other 90% of the development
time.
- T. Cargill |
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The sooner you start to code, the longer the program will take.
- R. Carlson |
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The important point is that the cost of adding a feature isn't just the time
it takes to code it.
The cost also includes the addition of an obstacle to future expansion.
Sure, any given feature list can be implemented, given enough coding time.
But in addition to coming out late, you will usually wind up with a codebase
that is so fragile that new ideas that should be dead-simple wind up taking
longer and longer to work into the tangled existing web.
The trick is to pick the features that don't fight each other.
- J. Carmack |
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We think too much about effective methods of teaching and not enough about
effective methods of learning.
No matter how good teaching may be, each student must take the responsibility
for his own education.
- J. Carolus S.J. |
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In a way, math isn't the art of answering mathematical questions, it is
the art of asking the right questions, the questions that give you insight,
the ones that lead you in interesting directions, the ones that connect with
lots of other interesting questions -the ones with beautiful answers.
- G. Chaitin (pg. 23, in "Meta Math: The Quest for Omega") |
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Mathematical truth is not totally objective.
If a mathematical statement is false, there will be no proofs, but if it is
true, thre will be an endless variety of proofs, not just one!
Proofs are not impersonal, they express the personality of their
creator/discoverer just as much as literary efforts do.
If something important is true, there will be many reasons that it is
true, many proofs of that fact.
Math is the music of reason, and some proofs sound like jazz, others sound
like a fugue.
Which is better, the jazz or the fugue?
Neither: it's all a matter of taste...each proof will emphasize different
aspects of the problem, each proof will lead in a different direction.
Each one will have different corollaries, different
generalizations...Mathematical facts are not isolated, they are woven into
a vast spider's web of interconnections.
- G. Chaitin (pg. 23, in "Meta Math: The Quest for Omega") |
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Any sufficiently advanced technology is indistinguishable from magic.
- A. Clarke |
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We don't have time to stop for gas, we're already late.
- M. Cleron (Commenting on how Software Projects are often Run) |
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Whenever there is a hard job to be done I assign it to a lazy man; he is sure
to find an easy way of doing it.
- W. Chrysler |
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The real technology -behind all our other technologies- is language.
It actually creates the world our consciousness lives in.
- A. Codrescu |
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I hear and I forget; I see and I remember; I do and I understand.
- Confucius |
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Never hesitate to ask a lesser person.
- Confucius |
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Press on.
Nothing in th world can take the place of persistence.
Talent will not; nothing is more common than unsuccessful men with talent.
Genius will not; unrewarded genius is almost a proverb.
Education alone will not; the world is full of educated derelicts.
Persistence and determination alone are omnipotent.
- C. Coolidge |
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Six jokes:
"What do you get when you cross a computer with an airplane?
What do you get when you cross a computer with a camera?
What do you get when you cross a computer with an alarm clock?
What do you get when you cross a computer with a car?
What do you get when you cross a computer with a bank?
What do you get when you cross a computer with a warship?"
In all six cases the answer is "A computer." [Cooper illustrates how the nature of these systems becomes dominated by the nature of their computer components] - A. Cooper (I'm paraphrasing some pictures and text appearing in "The Inmates are Running the Asylum") |
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The value of a prototype is in the education it gives you, not in the code
itself.
- A. Cooper (in "The Inmates are Running the Asylum") |
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When the words are fuzzy, the programmers reflexively retreat to the most
precise method of articulation available: source code.
Although there is nothing more precise than code, there is also nothing more
permanent or resistant to change.
So the situation frequently crops up where nomenclature confusion drives
programmers to begin coding prematurely, and that code becomes the
de facto design, regardless of its appropriateness or correctness.
- A. Cooper (in "The Inmates are Running the Asylum") |
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Doing more things faster is no substitute for doing the right things.
- S. R. Covey |
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The generation of random numbers is too important to be left to chance.
- R. Coveyou |
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If you don't think carefully, you might believe that programming is just
typing statements in a programming language.
- W. Cunningham |
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Who dares to teach must never cease to learn.
- J.C. Dana |
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Every now and then go away, have a little relaxation, for when you come
back to your work your judgment will be surer.
Go some distance away because then the work appears smaller and more of it can
be taken in at a glance and a lack of harmony and proportion is more readily
seen.
- L. Da Vinci |
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Simplicity is the ultimate sophistication.
- L. Da Vinci |
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If you cannot describe what you are doing as a process, you don't know what
you're doing.
- W. E. Deming |
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Question authority; but, raise your hand first.
- A. Dershowitz |
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One can think effectively only when one is willing to endure suspense and to
undergo the trouble of searching.
- J. Dewey |
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As long as there were no machines, programming was no problem at all; when we
had a few weak computers, programming became a mild problem, and now [1972]
that we have gigantic computers, programming has become a gigantic problem.
As the power of available machines grew by a factor of more than a thousand,
society's ambition to apply these new machines grew in proportion, and it was
the poor programmer who found his job in this exploded field of tension
between the ends and the means.
The increased power of the hardware, together with the perhaps more dramatic
increase in its reliability, made solutions feasible that the programmer had
not dared to dream about a few years before.

It is no wonder that we found ourselves in a software crisis
- E. Dijkstra (The Humble Programmer, "ACM Turing Award Lectures: The First 25 Years", Addison-Wesley, 1987, pages 17-32) |
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A most important, but also most elusive, aspect of any tool is its influence
on the habits of those who train themselves in its use.
If the tool is a programming language this influence is, whether we like it
or not, an influence on our thinking habits....
A programming language is a tool that has profound influence on our thinking
habits.
- E. Dijkstra |
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Being abstract is something profoundly different from being vague...
The purpose of abstraction is not to be vague, but to create a new semantic
level in which one can be absolutely precise.
- E. Dijkstra |
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Besides a mathematical inclination, an exceptionally good mastery of one's
native tongue is the most vital asset of a competent programmer.
- E. Dijkstra |
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Computer Science is no more about computers than astronomy is about telescopes.
- E. Dijkstra |
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If we wish to count lines of code, we should not regard them as lines
produced but as lines spent.
- E. Dijkstra |
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John von Neumann draws attention to what seemed to him a contrast.
He remarked that for simple mechanisms, it is often easier to describe how
they work than what they do, while for more complicated mechanisms, it is
usually the other way around.
- E. Dijkstra (Trip Reports, 213) |
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Object-oriented programming is an exceptionally bad idea which could only have
originated in California
- E. Dijkstra (note: OOP originated in Norway, quite near Holland -Dijkstra's home) |
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...our intellectual powers are rather geared to master static relations
and that our powers to visualize processes evolving in time are
relatively poorly developed.
For that reason we should do (as wise programmers aware of our limitations)
our utmost to shorten the conceptual gap between the static program and
the dynamic process, to make the correspondence between the program
(spread out in text space) and the process (spread out in time) as trivial
as possible.
- E. Dijkstra (in "Goto Considered Harmful") |
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Progress is possible only if we train ourselves to think about programs without
thinking of them as pieces of executable code.
- E. Dijkstra |
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Simplicity is prerequisite for reliability.
- E. Dijkstra |
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...Simplifications have had a much greater long-range scientific impact than
individual feats of ingenuity.
The opportunity for simplification is very encouraging, because in all examples
that come to mind the simple and elegant systems tend to be easier and faster
to design and get right, more efficient in execution, and much more reliable
than the more contrived contraptions that have to be debugged into some
degree of acceptability....Simplicity and elegance are unpopular because they
require hard work and discipline to achieve and education to be appreciated.
- E. Dijkstra (The Tide, not the waves; in Denning/Metcalfe: Beyond Calculation, Springer-Verlag 1997) |
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The tools we use have a profound (and devious!) influence on our thinking
habits, and, therefore, on our thinking abilities.
- E. Dijkstra |
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Testing can show the presence of errors, but not their absence.
- E. Dijkstra |
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The competent programmer is fully aware of the strictly limited size of his
own skull; therefore he approaches the programming task in full humility,
and among other things he avoids clever tricks like the plague.
- E. Dijkstra (in "The Humble Programmer", his 1972 Turing Award Lecture) |
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The art of programming is the arto of organizaing complexity, of mastering
multitude and avoiding its bastard chaos.
- E. Dijkstra (in "Notes on Structured Programmin") |
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We are all shaped by the tools we use, in particular: the formalisms we use
shape our thinking habits, for better or for worse, and that means that
we have to be very careful in the choice of what we learn and teach,
for unlearning is not really possible.
- E. Dijkstra (in Answers to Questions from Students of Sofware Engineering) |
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Yes, I share your concern: how to program well -though a teachable topic- is
hardly taught.
The situation is similar to that in mathematics, where the explicit curriculum
is confined to mathematical results; how to do mathematics is something the
student must absorb by osmosis, so to speak.
One reason for preferring symbol-manipulating, calculating arguments is that
their design is much better teachable than the design of verbal/pictorial
arguments.
Large-scale introduction of courses on such calculational methodology, however,
would encounter unsurmoutable political problems.
- E. Dijkstra (in Answers to Questions from Students of Sofware Engineering) |
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Text is linear; it is black and white; it doesn't zoom around the page in 3-D;
it isn't intelligent by itself; in fact, in terms of immediate reaction it is
quite boring.
I can't imagine a single preliterate was ever wowed at the first sight of
text, and yet text has been the basis of arguably the most fundamental
intellectual transformation of the human species.
It and its subforms, such as algebra, have made science education for all a
plausible goal.
- A.diSessa ("Changing Minds: Computers, Learning, and Literacy", MIT Press, 2000; page 112) |
|
There is nothing so useless as doing efficiently that which should not be
done at all.
- P. Drucker |
|
The first step in fixing a broken program is getting it to fail repeatably [on
the simplest example possible].
- T. Duff |
|
It's supposed to be hard!
If it wasn't hard, everyone would do it.
The hard... is what makes it great!"
- J. Dugan (said by Tom Hanks' character in "A League of Their Own" in response to a complaint from one of his ball players) |
|
Genius is 1 percent inspiration and 99 percent perspiration.
As a result, genius is often a talented person who has simply done all of his
homework.
- T. Edison |
|
Any intelligent fool can make things bigger, more complex, and more
violent.
It takes a touch of genius - and a lot of courage - to move in the opposite
direction.
- A. Einstein |
|
Everything should be made as simple as possible, but not simpler.
- A. Einstein |
|
Example isn't another way to teach.
It is the only way to teach.
- A. Einstein |
|
If you can't explain it simply, you don't understand it well enough.
- A. Einstein |
|
Imagination is more important than knowledge.
- A. Einstein |
|
Out of clutter, find simplicity.
From discord, find harmony.
In the middle of difficulty, lies opportunity.
- A. Einstein |
|
Reinventing the wheel is a process.
- R. Elisha |
|
To arrive at the simple is difficult.
- R. Elisha |
|
Shall I tell you the secret of the true scholar?
It is this: every man I meet is my master in some point, and in that I learn
of him.
- R.W. Emerson |
|
The proof of a high education is the ability to speak about complex matters
as simply as possible.
- R.W. Emerson |
|
The structure of a system reflects the structure of the organization that built
it.
- R. Fairley |
|
In those days [batch processing] programmers never even documented their
programs, because it was assumed that nobody else would ever use them.
Now, however, time-sharing had made exchanging software trivial: you just
stored one copy in the public repository and therby effectively gave it to
the world.
Immediately people began to document their programs and to think of them as
being usable by others.
They started to build on each other's work.
- R. Fano (in Waldrop, "The Dream Machine", pp. 232) |
|
Thus, writing a clever piece of code that works is one thing; designing
something that can support a long-lasting business is quite another.
Commercial software design and production is, or should be, a rigorous,
capital-intensive activity.
Software products should be based on a broad, deep structure that can support
much more than whatever the product contains at any given time.
In addition to code that works, you need documentation, help functions, error
handling, multi-platform support, and multiple languages.
You also need an underlying architecture that allows you to add and change
features, purchase and integrated external software components, and allows
other software vendors to make their products talk to yours, add customized
widgets to it, embed your product inside something larger of their own.
A good architecture, one that will carry you for a decade's worth of
unpredictable technology and marked changes, take months to develop.
But if you skip this step, as Netscape did, you have made a truly Faustian
bargain.
The problem with this [building just what you need, instead of planning ahead] is that these systems start getting ferociously complicated. It comes time to fix a mistake, add a feature, replace something and you discover that everything is connected to everything else in ways you can't even begin to understand. Because you're doing something more ambitious than the initial academic prototype, it's big enough that you need to partition it across a team. The members of the team need to have a clear idea of how their work relates to everyone else's, and they need to be able to communicate to the testers whose job it is to find errors. Otherwise [in other words], you give the patient a kidney transplant and his heart suddenly fails; then you give him a heart drug, but that makes his lungs collapse. You don't know why, and you're screwed. And then the future comes, and you're really screwed. Later releases of the product inevitably are more complex, because they must continue to support previous version while adding new capabilities. You discover that the original developers have quit or been promoted or have forgotten what they did, and it's time to keep up with the competition by adding new features, supporting more platforms, translating into Japanese, and so forth. The engineering team has to quadruple in size. You start discovering things like three different groups need to change the same piece of code, and each set of changes causes problems for the others, and nobody else can test their work until that piece of code is stable, so a hundred people twiddle their thumbs for a week. Or you want to use an existing function for some new purpose, but you can't isolate it from everything else, so you have to write it all over again. This not only means that you have the extra time and cost of writing and maintaining twice as much code, but you probably have to ensure that the two versions work exactly alike, which they almost certainly won't. With each successive release, these problems get worse. By the time you're on your fifth release, the decision to do your first product the quick and dirty way has probably cost you ten times what it originally saved. A program like Microsoft's Windows 98 is tens of millions of lines of code. Nobody can keep that much complexity in their head or hope to manage it effectively. So you need an architecture that says to everyone, "Here's how this thing works, and to do your part, you need to understand only these five things, and don't you dare touch anything else." - C. Ferguson (High Stakes, No Prisoners; Times Business Press, page 107-109) |
|
I can live with doubt and uncertainty.
I think it's much more intersting to live not knowing than to have answers
which might be wrong...
In physics the truth is rarely perfectly clear, and that is certainly
universally the case in human affairs.
Hence, what is not surrounded by uncertaintly cannot be the truth.
- R. Feynman (in "Perfectly Reasonable Deviations from the Beaten Track: The Letters of Richard P. Feynman") |
|
If you're teaching a class, you can think about the elementary things that you
know very well.
These things are kind of fun and delightful. It doesn't do any harm to think
them over again.
Is there a better way to present them?
The elementary things are easy to think about; if you can't think of a new
thought, no harm done; what you thought about it before is good enough for
the class.
If you do think of something new, you're rather pleased that you have a new
way of looking at it.
The questions of the students are often the source of new research. They often ask profound questions that I've thought about at times and then given up on, so to speak, for a while. It wouldn't do me any harm to think about them again and see if I can go any further now. The students may not be able to see the thing I want to answer, or the subtleties I want to think about, but they remind me of a problem by asking questions in the neighborhood of that problem. It's not so easy to remind yourself of these things. - R. Feynman (from "The Dignified Professor" in "Surely You're Joking Mr. Feynman: pg. 166) |
|
Precise language is not the problem.
Clear language is the problem.
- R.
- R. Feynman |
|
What I cannot create I do not understand.
- R. Feynman |
|
When the problem [quantum chromodynamics] is finally solved, it will all be
by imagination.
Then there will be some big thing about the great way it was done.
But it's simple -it will all be by imagination, and persistence.
- R. Feynman (in Mlodinow's "Feynman's Rainbow") |
|
When a Caltech student asked the eminent cosmologist Michael Turner what his
"bias" was in favoring one or another particle as a likely candidate
to compromise dark matter in the universe, Feynmann snapped, "Why do you
want to know his bias? Form your own bias!"
- R. Feynman (related by Timothy Ferris in "Perfectly Reasonable Deviations from the Beaten Track: The Letters of Richard P. Feynman") |
|
There does not now, nor will there ever exist, a programming language in which
it is the least bit hard to write bad programs.
- L. Flon |
|
An engineer can do for a nickel what any damn fool can do for a dollar.
- H. Ford |
|
Education's purpose is to replace an empty mind with an open one.
- M. Forbes |
|
Any fool can write code that a computer can understand.
Good programmers write code that humans can understand.
- M. Fowler, "Refactoring: Improving the Design of Existing Code" |
|
[Describing JUnit]
Never in the field of program testing, was so much owed by so many to so few
lines of code.
- M. Fowler (apologizing to Winston Churchill) |
|
Awaken people's curiosity.
It is enough to open minds, do not overload them.
Put there just a spark.
- A. France |
|
Simplicity is the soul of efficiency.
- A. Freeman (in The Eye of Osiris) |
|
When I am working on a problem, I never think about beauty.
I think only of how to solve the problem.
But when I have finished, if the solution is not beautiful, I know it is
wrong.
- B. Fuller |
|
The biggest difference between time and space is that you can't reuse time.
- M. Furst |
|
Habitability is the characteristic of source code that enables programmers
coming to the code later in its life to understand its construction and
intentions and to change it comfortably and confidently... Software needs
to be habitable because it always has to change...Programs are written and
maintained, bugs are fixed, features are added, performance is tuned, and
a whole variety of changes are made both by the original and new programming
team members... What is important is that it be easy for programmers
to come up to speed with the code, to be able to navigate through it
effectively, to be able to understand what changes to make, and to be able to
make them safely and correctly.
- R. Gabriel (Patterns of Software, Oxford Press 1996) |
|
All truths are easy to understand once they are discovered; the point is to
discover them.
- G. Galilie |
|
A complex system that works in invariably found to have evolved from a simple
system that worked.
- J. Gall |
|
An excellent plumber is infinitely more admirable than an incompetent
philosopher.
The society that scorns excellence in plumbing because plumbing is a humble
activity and tolerates shoddiness in philosophy because it is exalted
activity will have neither good plumbing or good philosophy.
Neither its pipes or its theories will hold water.
- J. Gardner |
|
640K [of main memory] ought to be enough for anybody.
- W. Gates (Founder and CEO Microsoft), 1981 - disclaimed |
|
A great lathe operator commands several times the wage of an average lathe
operator, but a great writer of software code is worth 10,000 times the price
of an average software writer.
- W. Gates |
|
The best way to prepare [to be a programmer] is to write programs, and to
study great programs that other people have written.
In my case, I went to the garbage cans at the Computer Science Center and
fished out listings of their operating systems.
- W. Gates |
|
We flew down weekly to meet with IBM, but they thought the way to measure
software was the amount of code we wrote, when really the better the
software, the fewer lines of code.
- W. Gates |
|
It is not knowledge, but the act of learning, not possession, but the act
of getting there which generates the greatest satisfaction.
- F. Gauss |
|
Beauty is more important in computing than anywhere else in technology because
software is so complicated.
Beauty is the ultimate defense against complexity.
...
The geniuses of the computer field, on the the other hand, are the
people with the keenest aesthetic senses, the ones who are
capable of creating beauty.
Beauty is decisive at every level: the most important interfaces, the most
important programming languages, the winning algorithms are the beautiful
ones.
- D. Gelernter ("Machine Beauty", Basic Books, 1998) |
|
Good programmers know what's beautiful and bad ones don't.
- D. Gelernter ("Machine Beauty", Basic Books, 1998) |
|
Object-oriented programming as it emerged in Simula 67 allows
software structure to be based on real-world structures, and
gives programmers a powerful way to simplify the design and
construction of complex programs.
- D. Gelernter ("Machine Beauty", Basic Books, 1998) |
|
One of the principal objects of theoretical research in any department of
knowledge is to find the point of view from which the subject appears in
its greatest simplicity.
- J. W. Gibbs |
|
Vague and nebulous is the beginning of all things, but not their end.
- K. Gibran |
|
At the source of every error which is blamed on the computer, you will find at
least two human errors, one of which is the error of blaming it on the
computer.
- T. Gilb (in "Laws of Unreliability", Datamation March 1975) |
|
Indirection is the right direction.
- A. Glew |
|
Never put off until run time what can be done at compile time.
- A.
- M. Golding |
|
This attitude [the abstract method in mathematics] can be encapsulated in
the following slogan: a mathematical object is what it does.
- T. Gowers (in "Mathematics: A Very Short Introduction pg. 18) |
|
A really good language should be both clean and dirty: cleanly designed,
with a small core of well understood and highly orthogonal operators,
but dirty in the sense that it lets hackers have their way with it....A real
hacker's language will always have a slightly raffish character.
- P. Graham (in "Hackers and Painters" pg. 204) |
|
Fixing fresh bugs is easier than fixing old ones.
It's usaully fairly quick to find a bug in code you just wrote.
When it turns up you often know what's wrong before you even look at the
source, because you were already worrying about it subconsciously.
Fixing a bug in something you wrote six months aga (the average case if you
release once a year) is a lot more work.
And since you don't understand the code as well, you're more likely to fix it
in an ugly way, or even introduce more bugs.
When you catch bugs early, you also get fewer compound bugs. Compound bugs are two separate bugs that interact: you trip going downstairs, and when you reach for the handrail it come off in your hand. In software this kind of bug is the hardest to find, and also tends to have the worst consequences. The traditional "break everything and then filter out the bugs" approach inherently yields a lot of compound bugs. And software released in a series of small chances inherently tends not to. The floors are constantly being swept clean of any loose objects that might later get stuck to something. - P. Graham (in "Hackers and Painters" pg. 65-66) |
|
Great software, likewise, requires a fanatical devotion to beauty.
If you look inside good software, you find that parts that no one is ever
supposed to see are beautiful too.
When it comes to code I behave in a way that would make me eligible for
prescription drugs if I approached everyday life the same way.

- P. Graham (in "Hackers and Painters" pg. 29) |
|
Imagine the kind of conversation you would have with someone so far away that
there was a transmission delay of one minute.
Now imagine speaking to someone in the next room.
You wouldn't just have the same conversation faster, you would have a different
kind of conversation.
In Lisp, developing software is like speaking face-to-face.
You can test code as you're writing it.
And instant turnaround has just as dramatic an effect on development as it
does on conversation.
You don't just write the same program faster; you write a different kind of
program.
- P. Graham (in "On Lisp") |
|
The difference between design and research seems to be a question of the
good versus the new.
Design doesn't have to be new, but it has to be good.
Research doesn't have to be good, but it has to be new.
I think these two paths converge at the top: the best design surpasses its
predecessors by using new ideas, and the best research solves problems that
are not only new, but worth solving.
So ultimately design and research are aiming for the same destination, just
approaching it from different directions.
- P. Graham (in "Hackers and Painters" footnote 9, pg. 224) |
|
The way to make programs easy to read is not to stuff them with comments...
A good programming language ought to be better for explaining software than
English.
You should only need comments when there is some kind of kludge you need to
warn readers about, just as on a road there are only arrows on parts with
unexpectedly sharp curves.
- P. Graham (in "Hackers and Painters" footnote 9, pg. 224) |
|
You should figure our programs as you're writing them, just as writers and
painters and achitects do.
Realizing this [programming as sketching] has real implications for software
design.
It means that a programming language should, above all, be malleable.
A programming language is for thinking of programs, not for expressing
programs you've already thought of.
It should be a pencil, not pen.
... Remember too that languages are not primarily a form for finished programs, but something that programs have to be developed in. ... A good programming language should, like oil paint, make it easy to change your mind. ... Paintings usually begin with a sketch. Gradually the details get filled in. But it is not merely a process of filling in. Sometimes the original plans turn out to be mistaken. Countless paintings, when you look at them in x-rays, turn out to have limbs that have been moved or facial features that have been readjusted. ... So the test of a language is not simply how clean the finished program looks in it, but how clean the path to the finished program was. ... What made oil paint so exciting, when it first became popular in the fifteenth century, was that you could make the finished work ... Building something by gradually refining a prototype is good for morale because it keeps you engaged. In software, my rule is: always have working code. If you're writing something you'll be able to test in an hour, you have the prospect of an immediate reward to motivate you. - P. Graham (in "Hackers and Painters" pg. 22, 27, 218, 219, 220, 221) |
|
Incidentally, when we're faced with a "prove or disprove," we're usually
better off trying first to disprove with a counterexample, for two reasons:
A disproof is potentially easier (we need just one counterexample); and
nitpicking arouses our creative juices.
Even if the given assertion is true, our search for a counterexample often
leads to a proof, as soon as we see why a counterexample is impossible.
Besides, it's healthy to be skeptical.
- R. Graham, D. Knuth and O. Patashnik (in "Concrete Mathematics: A Foundation for Computer Science") |
|
Any sufficiently complicated C or Fortran program contains an ad hoc
informally specified bug-ridden slow implementation of half of Lisp.
- P.
- D. Gwyn |
|
Any performance problem can be solved by removing a level of indirection.
(also see "Any programming problem..." by Anonymous).
- M. Haertel |
|
The tendency to err that programmers have been noticed to share with other
human beings has often been treated as though it were an awkwardness
attendant upon programing's adolescence, which like acne would disappear
with the craft's coming of age.
It has proved otherwise.
- M. Halpern |
|
The purpose of computing is insight, not numbers.
- R. Hamming |
|
- F. Hapgood |
|
The mathematician's patterns, like those of the painter's or the poet's,
the ideas, like the colours or words, must fit together in a harmonious
way.

- G.H. Hardy (in "A Mathematician's Apology") |
|
Programming is an explanatory activity.
- R. Harper |
|
It is very interesting to me how quickly the class has divided up into three
factions.
One faction being the students who sit in the back of the class, given up
sitting in their assigned seats, preparing the cases.
What is it, only October?
They've already given up trying -the cowards.
The second group are the ones who won't raise their hands or volunteer an
answer, but will try when they're called upon.
That's where I am right now, living in a state of constant fear.
And then there's the third echelon: the upper echelon; the volunteers.
They raise their hands in class.
They thrust themselves into the fray.
I don't think they're smarter than anyone else, but they have courage.
And, they'll achieve the final recognition, that teachers will get to
know their names, and they'll get better grades.
The past couple weeks I've been preparing to enter the upper echelon,
and this weekend -if I can get all my work done-
I'm going to enter it Monday morning, in Kingsfield's contract law class.
- James Hart (a law student in "The Paper Chase") |
|
[Breaking into the "red" room in the Harvard law library, which contains the
notes of Harvard professors from their school days, and drafts of their
articles and books]
Do you realize what this is?
This is it.
This is the unbroken chain.
The ageless passing of wisdom.
Hey [what is it?] listen to this.
"Kingsfield, Charles W. notes on contract lawy in the course
on contracts by Professor Williston at the Harvard Law School, 1927".

They're just notes: and they look just like mine.
Look [reading from Kingsfield's notes].
"Questions: Does everybody have a contract to obey everybody else's rights.
What is a contract?
What do you owe to others?"
Look, there are even doodles.
[C'mon, let's get outta here.]
Wait, wait.
"Can we make a contract with G-d that is biding to man?
...
After all, I am almost the living extension of the old judges.
Where would they be without me.
I carry in my mind the cases they wrote.
Where the hell woudl they be if it wasn't for me?
Who would hang their pictures if there were no law students?
It's hard being the living extension of tradition."
- James Hart (a law student in "The Paper Chase") |
|
There are features that should not be used.
There are concepts that should not be exploited.
There are problems that should not be solved.
There are programs that should not be written.
- R. Harter |
|
PROBLEMS Problems worthy of attack prove their worth by hitting back. - P.Hein (in "Grooks") |
|
THE ROAD TO WISDOM The road to wisdom? - Well, it's plain and simple to express: Err and err and err again but less and less and less. - P.Hein (in "Grooks") |
|
The one who insists on never uttering an error must remain silent.
- W. Heisenberg |
|
The speed of a non-working program is irrelevant.
- S. Heller (in "Efficient C/C++ Programming") |
|
Refactoring provides enough energy to a system for it to relax into a new and
more comfortable state, a new local minimum.
The effect of refactoring commonality is to tame the complexity of your system.
- K. Henney (in Minimalism: The Imperial Clothing Crisis) |
|
A process cannot be understood by stopping it.
Understanding must move with the flow of the process, must join and flow
with it.
- F. Herbert (The First Law of Mentat in "Dune") |
|
It's [programming] the only job I can think of where I get to be both an
engineer and an artist.
There's an incredible, rigorous, technical element to it, which I like
because you have to do very precise thinking.
On the other hand, it has a wildly creative side where the boundaries of
imagination are the only real limitation.
- A. Hertzfeld (original Mac programmer) |
|
...At first I hoped that such a technically unsound project would collapse but
I soon realized it was doomed to success.
Almost anything in software can be implemented, sold, and even used given
enough determination.
There is nothing a mere scientist can say that will stand against the flood of
a hundred million dollars.
But there is one quality that cannot be purchased in this way -and that is
reliability.
The price of reliability is the pursuit of the utmost simplicity.
It is a price which the very rich find most hard to pay.
- C.A.R. Hoare |
|
I was eventually persuaded of the need to design programming notations so as to
maximize the number of errors which cannot be made, or if made, can be
reliably detected at compile time.
- C.A.R. Hoare |
|
In the development of the understanding of complex phenomena, the most powerful
tool available to the human intellect is abstraction.
Abstraction arises from the recognition of similarities between certain
objects, situations, or processes in the real world and the decision to
concentrate on these similarities and to ignore, for the time being, their
differences.
- C.A.R. Hoare |
|
Inside every well-written large program is a well-written small program.
- C.A.R. Hoare |
|
Premature optimization is the root of all evil in programming.
- C.A.R. Hoare |
|
The unavoidable price of reliability is simplicity.
- C.A.R. Hoare |
|
There are two ways of constructing a software design.
One way is to make it so simple that there are obviously no deficiencies.
And the other way is to make it so complicated that there are no obvious
deficiencies.
- C.A.R. Hoare |
|
What is the central core of the subject [computer science]?
What is it that distinguishes it from the separate subjects with which it is
related?
What is the linking thread which gathers these disparate branches into a
single discipline.
My answer to these questions is simple -it is the art of programming a
computer.
It is the art of designing efficient and elegant methods of getting a computer
to solve problems, theoretical or practical, small or large, simple or
complex.
It is the art of translating this design into an effective and accurate
computer program.
- C.A.R. Hoare |
|
You cannot teach beginners top-down programming, because they don't know which
end is up.
- C.A.R. Hoare |
|
All thought is a kind of computation.
- D. Hobbes |
|
The problem is never how to get new, innovative thoughts into your mind,
but how to get old ones out!
- D. Hock (founder of VISA) |
|
Using a language we may create models of phenomena of interest,
and by using models, phenomena may be studied for purposes of
understanding or prediction.
Models may be used for analysis focussed on a close examination of
individual parts of the model and for synthesis aimed at
understanding the interplay of the parts, that is, understanding
the model as a whole.
A novel is like a model of the real world expressed in a written
languagee like English.
In a novel, the characters may be analyzed and the interaction between
people may be displayed and studied.
(in "Dreams of Calculus: Perspectives on Mathematics Education")
- J. Hoffman, C. Johnson, A. Logg |
|
The ability to simplify means to eliminate the unnecessary so that the
necessary may speak.
- H. Hofmann (in "Introduction to the Bootstrap") |
|
This sequence [of languages, SP/1 through SP/8] solves one of the perennial
problems of introductory programming.
As J.J. Horning once put it, the subject requires that everything must be
taught first.
- R. Holt, D. Wortman, D. Barnard and J. Cordy (quoting J.J. Horning) in "SP/k: A System for Teaching Computer Programming", CACM 20/5 (May 77) pg. 303 |
|
A ship in port is safe, but that is not what ships are built for.
I want all the youngsters to sail out to sea and be good ships.
- G. Hopper |
|
When you have a good idea and you've tried it and you know it's going to
work, go ahead and do it -because it's much easier to apologize afterwards
than it is to get permission.
- G. Hopper |
|
Computer Science is the only discipline in which we view adding a new wing to a
building as being maintenance.
- J. Horning |
|
To treat programming scientifically, it must be possible to specify the
required properties of programs precisely. Formality is certainly not an end
in itself.
The importance of formal specifications must ultimately rest in their utility
-in whether or not they are used to improve the quality of software or to
reduce the cost of producing and maintaining software.
- J. Horning |
|
One purpose of CRC cards [a design tool] is to fail early, to
fail often, and to fail inexpensively.
It is a lot cheaper to tear up a bunch of cards that it would be
to reorganize a large amount of source code.
- C. Horstmann (in Object-Oriented Design with Java) |
|
We [teachers] make the road, others will make the journey.
- V. Hugo |
|
The greatest mistake you can make is to be continually fearing you will make
one.
- E. Hubbard |
|
Rules of Optimization:   Rule 1: Don't do it.   Rule 2 (for experts only): Don't do it yet. - M. A. Jackson |
|
In the practical use of our intellect, forgetting is as important as remembering.
- W. James |
|
That simplicity is the ultimate sophistication.
What we meant by that was when you start looking at a problem and it seems
really simple with all these simple solutions, you don't really understand
the complexity of the problem.
And your solutions are way too oversimplified, and they don't work.
Then you get into the problem, and you see it's really complicated.

That's sort of the middle, and that's where most people stop, and the
solutions tend to work for a while.
But the really great person will keep on going and find, sort of, the key,
underlying principle of the problem.
And come up with a beautiful elegant solution that works.
- S. Jobs (in "The Perfect Thing" by Steven Levy, pg. 67-68) |
|
The only problem with Microsoft is they just have no taste.
They have absolutely no taste.
What that means is -I don't mean that in a small way; I mean that in a
big way- is the sense that they don't think of original ideas.
They don't bring much culture into their product.
...
So I guess I am saddened not by Microsoft's success -I have no problem
with their success; they've earned their success (for the most part).
I have a problem with the fact that the just make really third-rate products.
- S. Jobs (transcribed from "Triumph of the Nerds") |
|
Before software can be reusable it first has to be usable.
- R. Johnson |
|
The fastest algorithm can frequently be replaced by one that is almost as fast
and much easier to understand.
- D. Jones |
|
To teach is to learn twice.
- J. Joubert |
|
The honest truth is that having a lot of people staring at the
code does not find the really nasty bugs. The really nasty bugs are
found by a couple of really smart people who just kill themselves.
(also see "Given enough eyeballs..." by E. Raymond).
- B. Joy |
|
We don't manage our time as well as we manage our space.
There's an overhead of starting and an overhead of stopping a project because
you kind of lose your momentum.
And you've got to bracket and put aside all the things you're already doing.
So you need reasonably large blocks of uninterrupted time if you're going to be
successful at doing some of these things.
That's why hackers tend to stay up late.
If you stay up late and you have another hour of work to do, you can just stay up another hour later without running into a wall and having to stop. Whereas it might take three or four hours if you start over, you might finish if you just work that extra hour. If you're a morning person, the day always intrudes a fixed amount of time in the future. So it's much less efficient. Which is why I think computer people tend to be night people -because a machine doesn't get sleepy. - B. Joy |
|
In the particular is contained the universal.
- J. Joyce |
|
Mistakes are the portals of discovery.
- J. Joyce |
|
90% of code written today is getting around other people's mistakes.
- A. Kay |
|
Computers are to computing as instruments are to music.
Software is the score whose interpretations amplifies our reach and lifts our
spirits.
Leonardo da Vinci called music the shaping of the invisible,
and his phrase is even more apt as a description of software.
- A. Kay |
|
[In a programming language] Simple things should be simple and complex things
should be possible.
- A. Kay |
|
The best way to predict the future is to invent it.
- A. Kay |
|
Until real software engineering is developed, the next best practice is to
develop with a dynamic system that has extreme late binding in all aspects.
- A. Kay |
|
When you can measure what you are speaking about, and express it in
numbers, you know something about it; but when you cannot measure it,
when you cannot express it in numbers, your knowled is of a meager and
unsatisfactory kind.
- Lord Kelvin |
|
Should array indices start at 0 or 1?
My compromise of 0.5 was rejected without, I thought, proper consideration.
- S. Kelly-Bootle |
|
If you have a large number of unrelated ideas, you have to get quite a distance
away from them to get a view of all of them, and this is the role of
abstraction.
If you look at each too closely you see too many details.
If you get far away things may appear simpler because you can only see the
large, broad outlines; you do not get lost in petty details.
- J. Kemeny (co-creator of the BASIC programming language) |
|
Act in haste and repent at leisure; code too soon and debug forever.
- R. Kennington |
|
Controlling complexity is the essence of computer programming.
- B. Kernighan |
|
Everyone knows that debugging is twice as hard as writing a program in the
first place.
So if you are as clever as you can be when you write it, how will you
ever debug it?
- B. Kernighan |
|
Another effective [debugging] technique is to explain your code to someone
else.
This will often cause you to explain the bug to yourself.
Sometimes it takes no more than a few sentences, followed by an embarrassed
"Never mind, I see what's wrong. Sorry to bother you."
This works remarkably well; you can even use non-programmers as listeners.
One university computer center kept a teddy bear near the help desk.
Students with mysterious bugs were required to explain them to the bear before
they could speak to a human counselor.
- B. Kernighan & D. Pike (in "The Practice of Programming" pp. 123) |
|
The only way to learn a new programming language is by writing programs in it.
- B. Kernighan & D. Ritchie |
|
The study of law is something new and unfamiliar to most of you -unlike any
schooling you have ever been through before.
We use the Socratic method here:
I call on you, ask you a question, and you answer it.
Why don't I just give you a lecture?
Because through my questions you learn to teach yourselves.
Through this method of questioning-answering, questioning-answering, we seek
to develop in you the ability to analyze that vast complex of facts that
constitute the relationships of members within a given society.
Questioning and answering.
At times, you may feel that you have found the correct answer.
I assure you that this is a total delusion on your part.
You will never find the correct, absolute, and final answer.
In my classroom, there is always another question, another question to follow
your answer.
Yes, you are on a treadmill.
My little questions spin the tumblers of your mind.

We do brain surgery here.
You teach yourselves the law, but I train your mind.

- Professor Kingsfield (addressing 1st year Harvard Law Students in "The Paper Chase") |
|
A charlatan makes obscure what is clear; a thinker makes clear what is obscure.
- H. Kingsmill |
|
Beware of bugs in the above code; I have only proved it correct, not tried it.
- D. Knuth |
|
Computers are good at following instructions, but not at reading your mind.
- D. Knuth (Tex, pg. 9) |
|
Debugging is an art that needs much further study ....
The most effective debugging techniques seem to be those which are designed
and built into the program itself -many of today's best programmers will
devote nearly half of their programs to facilitating the debugging process
on the other half; the first half... will eventually be thrown away, but the
net result is a surprising gain in productivity.
Another good debugging practice is to keep a record of every mistake that is made. Even though this will probably be quite embarrassing, such information is invaluable to anyone doing research on the debugging problem, and it will also help you learn how to reduce the number of future errors. - D. Knuth (The Art of Computer Programming, Volume 1) |
|
Let us change our traditional attitude to the construction of programs.
Instead of imagining that our main task is to instruct a computer what to do,
let us concentrate rather on explaining to human beings what we want a
computer to do.
- D. Knuth |
|
...methods are more important than facts.
The educational value of a problem given to a student depends mostly on how
often the thought processes that are invoked to solve it will be helpful in
later situations.
It has little to do with how useful the answer to the problem may be.
On the other hand, a good problem must also motivate the students; they
should be interested in seeing the answer.
Since students differ so greatly, I cannot expect everyone to like the problems
that please me.
- D. Knuth (in "Are Toy Problems Useful", Chapter 10 of "Selected Papers on Computer Science", pg. 176) |
|
...methods are more important than facts.
The educational value of a problem given to a student depends mostly on how
often the thought processes that are invoked to solve it will be helpful in
later situations.
It has little to do with how useful the answer to the problem may be.
On the other hand, a good problem must also motivate the students; they
should be interested in seeing the answer.
Since students differ so greatly, I cannot expect everyone to like the problems
that please me.
- D. Knuth (in "Are Toy Problems Useful", Chapter 10 of "Selected Papers on Computer Science", pg. 176) |
|
...One of the most important lessons, perhaps, is the fact that SOFTWARE IS
HARD.
From now on I shall have significantly greater respect for every successful
software tool that I encounter.
During the past decade I was surprised to learn that the writing of programs
for TeX and Metafont proved to be much more difficult than all the other
things I had done (like proving theorems or writing books).
The creation of good software demand a significiantly higher standard of
accuracy than those other things do, and it requires a longer attention
span than other intellectual tasks.
- D. Knuth (in "Selected Papers on Computer Science", pp 161) |
|
We should forget about small efficiencies, say about 97% of the time:
premature optimization is the root of all evil.
- D. Knuth |
|
When I speak about computer programming as an art, I am thinking primarily of
it as an art form, in an aesthetic sense.
The chief goal of my work as an educator and author is to help people learn
how to write beautiful programs...My feeling is that when we prepare
a program, the experience can be just like composing poetry or music...Some
programs are elegant, some are exquisite, some are sparkling.
My claim is that it is possible to write grand programs, noble
programs, truly magnificent ones!...computer programming is an art,
because it applies accumulated knowledge to the world, because it requires
skill and ingenuity, and especially because it produces objects of beauty.
Programmers who subconsciously view themselves as artists will enjoy what they
do and will do it better.
- D. Knuth (Computer Programming as an Art. Turing Award Speech 1974) |
|
When certain concepts of TeX are introduced informally, general rules will be
stated; afterwards you will find that the rules aren't strictly true.
In general, the later chapters contain more reliable information than the
earlier ones do.
The author feels that this technique of deliberate lying will actually make
it easier for you to learn the ideas.
Once you understand a simple but false rule, it will not be hard to supplement
that rule with its exceptions.
- D. Knuth (Tex, pg. vi) |
|
If we really understand the problem, the answer will come out of it,
because the answer is not separate from the problem.
- J. Krishnamurti |
|
Any sufficiently advanced bug is indistiguishable from a feature. - R. Kulawiec |
|
There is a race between the increasing complexity of the systems we build
and our ability to develop intellectual tools for understanding their
complexity.
If the race is won by our tools, then systems will eventually become easier
to use and more reliable.
If not, they will continue to become harder to use and less reliable for all
but a relatively small set of common tasks.
Given how hard thinking is, if those intellectual tools are to succeed,
they will have to substitute calculation for thought.
- L. Lamport |
|
"Where have you performed?" Murray asked me from behind a copy of Variety.
"Well, I don't perform, exactly," I answered, "but I have spoken at
synagogues, and I lecture from time to time at colleges and universities."
"Universities?" Murray sputtered. "Did he say universities? Worst audience in the world. I spoke at a university once. They invited me to speak about the hotel industry. Believe me, I've got a pretty good routine on this; I've used it many times before, and I know where I'm supposed to get reactions: chuckles, laughs, applause. Son of a bitch, I stand up there and it's a grim audience! All these young people in jeans and sneakers. I open it up for questions.  I realized later, they weren't an audience, they were students. They take notes and get grades. They're not there to laugh. Who wants to perform for an audience like that?" - A. Lansky, relating his experiences lecturing at resorts in the Catskills while raising money for the National Yiddish Book Center (described in his book, "Outwitting History") |
|
We think only through the medium of words.
Languages are true analytical methods.
Algebra, which is adapted to its purpose in every species of expression,
in the most simple, most exact, and best manner possible, is at the same
time a language and an analytical method.
The art of reasoning is nothing more than a language well arranged.
- A. Lavoisier |
|
We don't have much time, so we don't teach them; we acquaint them with things
that they can learn.
- C. Leiserson (on "The Undergraduate Practicum" at MIT, from a talk at CMU) |
|
Learning is never done without errors and defeat.
- V. Lenin |
|
If you want truly to understand something, try to change it.
- K. Lewin |
|
A vivid confirmation of this analysis [the importance of extra-curricular
activities] occurred during a lunchtime conversation I had with three
computer science graduates of the classes of 1994/1995 who started a company
together and sold it in 1998 for more than $250 million.
Over sandwiches I asked them what part of their computer science education had
been most important to the success of their software enterprise.
After a moment of tight smiles and awkward silence, one of the young graduates
spoke up.
"The computer science courses I took were really terrific," he said in an
attempt to reassure me, "but I didn't learn much that I could not have
learned on my own.
The most important things I learned were from managing the Quincy House Grill."
It made perfect sense -hiring, firing, and inspiring colleagues, working under
pressure in close quarters- all were very much the same in the
cheeseburger-flipping business he had run at Harvard as in the software
business the three had started in a tiny apartment.
- H. Lewis (in "Excellence Without Soul", pg. 88) |
|
...fielding statistics made sense only as numbers, not as language.
Language, not numbers, is what interested him
[Bill James, a baseball writer].
Words, and the meaning they were designed to convey.
"When the numbers acquire the significance of the language," he later wrote,
"they acquire the power to do all the things which language can do:
to become fiction and drama and poetry."
- M. Lewis (in Moneyball: The Art of Winning an Unfair Game, page 67) |
|
Complexity is a sign of technical immaturity.
Simplicity of use is the real sign of a well design product whether it is an
ATM or a Patriot missile.
- D. Ling |
|
Composing computer programs to solve scientific problems is like writing
poetry.
You must choose every word with care and link it with the other words in
perfect syntax.
There is no place for verbosity or carelessness.
To become fluent in a computer lnaguage demands almost the antithesis of
modern loose thinking.
It requires many interactive sessions, the hands-on use of the device.
You do not learn a foreign language from a book, rather you have to live
in the country for year to let the langauge become an automatic part of
you, and the same is true for computer languages.
- James Lovelock (Originator of the Gaia Theory) |
|
In the beginning we must simplify the subject, thus unavoidably falsifying it,
and later we must sophisticate away the falsely simple beginning.
- M. Maimonides |
|
Development is maintenance.
- B. Marick |
|
A teacher's job is to take a bunch of live wires and see that they are
well-grounded.
- D. Martin |
|
If our designs are failing due to the constant rain of changing requirements,
it is our designs that are at fault.
We must somehow find a way to make our designs resilient to such changes and
protect them from rotting.
- R. Martin |
|
If the only tool you have is a hammer, you tend to see every problem as a nail.
- A. Maslow |
|
Any clod can have the facts; having opinions is an art.
- C. McCabe |
|
Good code is its own best documentation.
As you're about to add a comment, ask yourself,
"How can I improve the code so that this comment isn't needed?"
Improve the code and then document it to make it even clearer.
- S. McConnell |
|
It's hard enough to find an error in your code when you're looking for it;
it's even harder when you've assumed your code is error-free.
- S. McConnell |
|
It's OK to figure out murder mysteries, but you shouldn't need to figure out
code.
You should be able to read it.
- S. McConnell |
|
Testing by itself does not improve software quality.
Test results are an indicator of quality, but in and of themselves, they
don't improve it.
Trying to improve software quality by increasing the amount of testing is
like try to lose weight by weighing yourself more often.

If you want to lose weight, don't buy a new scale; change your diet.
If you want to improve your software, don't test more; develop better.
- S. McConnell |
|
Formal methods will never have a significant impact until they can be used by
people who don't understand them.
- T. Melham |
|
Programming is similar to a game of golf.
The point is not getting the ball in the hole but how many strokes it takes.
- H. Mills |
|
The only way for errors to occur in a program is by being put there by
the author.
No other mechanisms are known.
Programs can't acquire bugs by sitting around with other buggy programs.
Right practice aims at preventing insertion of errors and, failing that,
removing them before testing or any other running of the program.
- H. Mills |
|
Making the simple complicated is commonplace; making the complicated simple,
awesomely simple, that's creativity.
- C. Mingus |
|
A computer is like a violin.
You can imagine a novice trying first a phonograph and then a violin.
The latter, he says, sounds terrible.
That is the argument we have heard from our humanists and most of our
computer scientists.
Computer programs are good, they say, for particular purposes, but they
aren't flexible.
Neither is a violin, or a typewriter, until you learn how to use it.
- M. Minsky (in "Why Programming Is a Good Medium for Expressing Poorly-Understood and Sloppily-Formulated Ideas") |
|
Language designers are not intellectuals.
They're not as interested in thinking as you might hope.
They just want to get a language done and start using it.
- D. Moon |
|
He who hasn't hacked assembly langauge as a youth has no heart.
He who does so as an adult has no brain.
- J Moore |
|
Computer science is to biology what calculus is to physics.
It's the natural mathematical technique that best maps the character
of the subject.
- H. Morowitz |
|
A little inaccuracy sometimes saves tons of explanation.
- H.H. Munro |
|
You have to honor failure, because failure is just the negative space around
success.
- R. Nelson (in Wired 06/2004 page 166) |
|
Computing is not about computers any more. It is about living.
- N. Negroponte |
|
Between 1892 say, and 1904, movies were made by the cameraman because he
understood the equipment.
And that is exactly where we are now [in software design].
In 1904 they invented the director; what was the director?
It was the guy who didn't have to know how to load the camera
didn't have to know how to sew costumes, play a violin, dance, fence,
or hang the lights.
But, he had to know how to make those effects come together in a unified
experience...
Why are video games so much better designed than office
software?

Office software is designed by people who want to do something
else on the weekend...
What does showbusiness teach you. It teaches you that
design is war; it is a power struggle between the producers, directors,
authors, everyone who wants to be involved.
- T. Nelson (transcribed from a talk at Engelbart's Unfinished Revolution a Stanford University Symposium) |
|
In mathematics you don't understand things.
You just get used to them.
- J. von Neumann |
|
Millions for compilers, but hardly a penny for understanding human programming
language use.
Now, programming languages are obviously symmetrical, the computer on one
side, the human on the other.
In an appropriate science of computer languages, one would expect that half
the effort would be on the computer side, understanding how to translate
the languages into executable form, and half on the human side, understanding
how to design languages that are easy or productive to use.
Yet, we do not even have an enumeration of all the psychologicial functions
programing languages serve for the user.
Of course, there is lots of programming language design, but it comes
from computer scientists.
And though technical papers on languages contain main appeals to ease of use
and learning, they patently contain almost no psychologicial evidence nor any
appeal to psychological science.
- A. Newell and S. Card |
|
There is no reason anyone would want a computer in their home.
- K. Olsen (Founder and President, Digital Equipment Corporation), 1977 |
|
The best performance improvement is the transition from the nonworking state
to the working state
- J. Osterhout |
|
Complexity kills.
It sucks the life out of developers, it makes products difficult to plan,
build and test, it introduces security challenges and it causes end-user
and administrator frustration.
...[we should] explore and embrace techniques to reduce complexity.
- R. Ozzie |
|
As a rule, software systems do not work well until they have been used, and
have failed repeatedly, in real applications.
- D. Parnas |
|
A programming language is like a natural, human language in that it favors
certain methaphors, images, and ways of thinking.
- S. Papert (in "Mindstorms: Children, Computers, and Powerfule Ideas", 1980) |
|
My basic idea is that programming is the most powerful medium of developing
the sophisticated and rigorous thinking needed for mathematics, for
grammar, for physics, for statistics, for all the "hard" subjects....
In short, I believe more than ever that programming should be a key part of
the intellectual development of people growing up.
- S. Papert (in "CACM January 2005 (Vol 24, #1, pp38)") |
|
I have made this letter longer than usual, only because I have not had
the time to make it shorter.
- B. Pascal |
|
Chance favors the prepared mind.
- L. Pasteur |
|
A class, in Java, is where we teach objects how to behave.
- R. Pattis |
|
Code should run as fast as necessary, but no faster; something important is
always traded away to increase speed.
- R. Pattis |
|
He who runs an av-rage pace, runs alone throughout the race. [I know I'm teaching at the right pace when I please no one: half the students say I'm going too slow, half too fast.] - R. Pattis |
|
If you cannot grok the overall structure of a program while taking a shower
[e.g., with no external memory aids], you are not ready to code it.
- R.
- R. Pattis |
|
The discipline of programming is most like sorcery.
Both use precise language to instruct inanimate objects to do our bidding.
Small mistakes in programs or spells can lead to completely unforseen
behavior: e.g., see the story, "The Sorcerer's Apprentice".
Neither study is easy: "...her [Galinda's] early appetite for sorcery
had waned once she'd heard what a grind it was to learn spells and,
worse, to understand them." from the book "Wicked" by G. Maguire.
- R. Pattis |
|
The purpose of brakes on a car is to allow you to go fast.

The purpose of a strict compiler (one that performs type checking,
uninitialized variable checking, reachability analysis, etc.) is to allow
you to program fast.
Programmers -like all humans- have limited intellects: when they focus on
one aspect of a program, they must ignore others.
Focusing on the right aspect at the right time is critical.
By understanding those aspects that the compiler can check, you can
ignore them, and focus on more important ones.
Some programmers think that such an approach is reckless; they believe that
you must pay close attention to everything at once.
They are right -for them; but I'm just not that smart, so I must use my
tools more effectively.
- R. Pattis |
|
The structure of a software system provides the ecology in which code is born,
matures, and dies.
A well-designed habitat allows for the successful evolution of all the
components needed in a software system.
- R. Pattis |
|
The three most important aspects of debugging and real estate are the same:
Location, Location, and Location.
- R. Pattis |
|
There is a famous rule in performance optimization called the 90/10 rule: 90%
of a program's execution time is spent in only 10% of its code.
The standard inference from this rule is that programmers should find that 10%
of the code and optimize it, because that's the only code where improvements
make a difference in the overall system performance.
But a second inference is just as important: programmers can deoptimize the
other 90% of the code (in order to make it easier to use, maintain, etc.),
because deterioration (of performance) of that code won't make much of a
difference in the overall system performance.
- R. Pattis |
|
When debugging, novices insert corrective code; experts remove defective code.
- R. Pattis |
|
When teaching a rapidly changing technology, perspective is more important
than content.
- R. Pattis |
|
When building a complex system, having crackerjack programmers
(who can make any design work, even a bad one) can be a liability.
The result, after lots of effort, is a working system that cannot
be easily maintained or upgraded.
Good -but not great- programmers would fail early, causing a realization
that the system must be redesigned, and then reimplemented.
The extra cost is paid once, early in the system's cycle (when it is
cheap), instead of repeatedly paid late in the system's cycle (when
it is more expensive).
- R. Pattis |
|
Don't tell people how to do things.
Tell them what to do and let them surprise you with their results.
- G. Patton |
|
The best way to get a good idea is to get a lot of ideas.
- L. Pauling |
|
A good programming language is a conceptual universe for thinking about
programming.
- A. Perlis |
|
A language that doesn't affect the way you think about programming is not
worth knowing.
- A. Perlis |
|
Any noun can be verbed.
- A. Perlis |
|
Fools ignore complexity; pragmatists suffer it; experts avoid it; geniuses
remove it.
- A. Perlis |
|
I think it is inevitable that people program poorly.
Training will not substantially help matters.
We have to learn to live with it.
- A. Perlis |
|
I think that it's extraordinarily important that we in computer science keep
fun in computing.
When it started out, it was an awful lot of fun.
Of course, the paying customers got shafted every now and then, and after a
while we began to take their complaints seriously.
We began to feel as if we really were responsible for the successful,
error-free perfect use of these machines.
I don't think we are.
I think we're responsible for stretching them, setting them off in new
directions, and keeping fun in the house.
I hope the field of computer science never loses its sense of fun.
- A. Perlis |
|
It goes against the grain of modern education to teach students to program.
What fun is there to making plans, acquiring discipline, organizing thoughts,
devoting attention to detail, and learning to be self critical.
- A. Perlis |
|
It is easier to write an incorrect program than understand a correct one.
- A. Perlis |
|
Optimization hinders evolution.
- A. Perlis |
|
Simplicity does not precede complexity, but follows it.
- A. Perlis |
|
There are two ways to write error-free programs,
but only the third one works. - A. Perlis |
|
To understand a program, you must become both the machine and the program.
- A. Perlis |
|
You think you KNOW when you learn, are more sure when you can write, even more
when you can teach, but certain when you can program.
- A. Perlis |
|
Computers are useless. They only give you answers.
- P. Picasso |
|
I am always doing that which I cannot do, in order that I may learn how to
do it.
- P. Picasso |
|
Fancy algorithms are slow when N is small, and N is usually small.
- R. Pike |
|
Fancy optimizers have fancy bugs.
- R. Pike |
|
Thinking and spoken discourse are the same thing, except that what we call
thinking is, precisely, the inward dialogue carried on by the mind with
itself without spoken sound.
- Plato |
|
The mind is not a vessel to be filled, but a fire to be ignited.
- Plutarch (See W.B. Yeats: Education...) |
|
Life is good only for two things: to study mathematics and to teach it.
- M. Poisson |
|
Computers in the future may weigh no more than 1.5 tons.
- Popular Science (1959) |
|
Knowledge of a subject means knowledge of the language of that subject, which
includes not only what its words mean, but far more important, how its words
mean.
As one learns the language of a subject, one is also learning what the subject
is.
It cannot be said often enough that what we call a subject consists mostly,
if not entirely, of its language. If you eliminate all the words of a
subject, you have eliminated the subject.
Biology is not plants and animals. It is language about plants and animals.
History is not events.
It is language describing and interpreting events.
Astronomy is not planets and stars.
It is a way of talking about planets and stars.
- N. Postman |
|
Gates has always understood Moore's Law better than anyone else in the
industry.
If you can make something run at all, get it out there -it may be slow and
clunky, but hardware improvements will bail you out.
If you wait until it's running perfectly on the hardware already in the field,
it will be obsolete before it's released.
This philosophy built Microsoft and is the main reason Microsoft won the war
IBM declared back in the OS/2 days.
- J. Pournelle (Dr. Dobbs Journal, Feb. 2004, pp. 89) |
|
The voyage of discovery is not in seeking new landscapes but in having new
eyes.
- M. Proust |
|
I really hate this darn machine;     I wish that they would sell it. It won't do what I want it to,     but only what I tell it. - Programmer's Lament |
|
Given enough eyeballs, all bugs are shallow (e.g., given a large enough
beta-tester and co-developer base, almost every problem will be characterized
quickly and the fix obvious to someone).
(also see "The honest truth..." by B. Joy).
- E. Raymond (Lesson 8 in The Cathedral and the Bazaar) |
|
Good programmers know what to write.
Great ones know what to use.
[I'd add: Exceptional programmers know how to write code that others can
use. -REP]
- E. Raymond |
|
Ugly programs are like ugly suspension bridges: they're much more liable to
collapse than pretty ones, because the way humans (especially
engineer-humans) perceive beauty is intimately related to our ability to
process and understand complexity.
A language that makes it hard to write elegant code makes it hard to write
good code.
- E. Raymond |
|
Computer Science is the first engineering discipline in which the complexity of
the objects created is limited solely by the skill of the creator, and not
by the strength of raw materials.
- B. Reid |
|
All of us had been trained by Kelly Johnson [designer of the Lockheed SR-71]
and believed fanatically in his insistence that an airplane that looked
beautiful would fly the same way.
- B. Rich (in "Skunk Works") |
|
In time of profound change, the learners inherit the earth, while the learned
find themselves beautifully equipped to deal with a world that no longer
exists.
- A. Rogers |
|
God is in the details.
- M. van der Rohe |
|
Less is more.
- M. van der Rohe |
|
Software is abstract and therefore seems as if it should be infinitely
malleable.
And yet, for all its ethereal flexibility, it can be stubbornly, maddeneningly
intractable, and it is constantly surprising us with his rigidity.
- S. Rosenberg (in "Dreaming in Code", pp 58) |
|
Don't you hate code that's not properly indented?
Making it [indenting] part of the syntax guarantees that all code is properly
indented.
- G. van Rossum(designer of the Python) |
|
The highest reward for a person's toil is not what they get for it, but what
they become by it.
- J. Ruskin |
|
Language serves not only to express thought but to make possible thoughts which
could not exist without it.
- B. Russell |
|
A designer knows he's achieved perfection not when there is nothing left to
add, but when there is nothing left to take away.
- A. de Saint-Exupery |
|
If you want to build a ship, don't drum up the men to gather wood, divide the
work and give orders.
Instead, teach them to yearn for the vast and endless sea.
- A. de Saint-Exupery |
|
Questions are the important thing, answers are less important.
Learning to ask a good question is the heart of intelligence.
Learning the answer---well, answers are for students.
Questions are for thinkers.
- R. Schank (in "The Connosseur's Guide to the Mind") |
|
There is one very good reason to learn programming, but it has nothing to do
with preparing for high-tech careers or with making sure one is computer
literate in order to avoid being cynically manipulated by the computers of
the future.
The real value of learning to program can only be understood if
we look at learning to program as an exercise of the intellect, as a kind of
modern-day Latin that we learn to sharpen our minds.
- R. Schank (in "The Cognitive Computer) |
|
Always do the hard part first.
If the hard part is impossible, why waste time on the easy part?
Once the hard part is done, you're home free.
Always do the easy part first. What you think at first is the easy part often turns out to be the hard part. Once the easy part is done, you can concentrate all your efforts on the hard part. - A. Schapira |
|
The skill of writing is to create a context in which other people can think.
- E. Schlossberg |
|
Machines are simple: a hammer, a door hinge, a steak knife.
Systems are much more complicated; they have components, feedback loops, mean
times between failure, infrastructure.
Digital systems are daedal; even a simple computer program has hundreds of
thousands of lines of computer code doing all sorts of different things.
A complex computer program has thousands of components, each of which has to
work by itself and in interaction with all the other components.
This is why object-oriented programming was developed: to deal with the
complexity of digital systems...systems have bugs.
A bug is a particular kind of failure...It's different from a malfunction.
When something malfunctions, it no longer works properly.
When something has a bug, it misbehaves in a particular way, possibly
unrepeatable, and possibly unexplainable.
Bugs are unique to systems.
Machines can break, or fail, or not work, but only a system can have a bug.
- B. Schneier (in Secrets & Lies: Digital Security in a Networked World). |
|
Microsoft knows that reliable software is not cost effective.
According to studies, 90% to 95% of all bugs are harmless.
They're never discovered by users, and they don't affect performance.
It's much cheaper to release buggy software and fix the 5% to 10% of bugs
people find and complain about.
- B. Schneier |
|
If the code and the comments disagree, then both are probably wrong.
- N. Schryer |
|
Always to see the general in the particular is the very foundation of genius.
- A. Schopenhauer |
|
Thus the task is not so much to see what no one has yet seen, but to think
what no one has yet throught about that which everybody sees.
- E. Schrodinger |
|
Data is not information,
Information is not knowledge,
Knowledge is not understanding,
Understanding is not wisdom.
- Gary Schubert (extending Cliff Stoll in "Silicon Snake Oil") |
|
Any intelligent fool can make things bigger and more complex.
It takes a touch of genius -and a lot of courage- to move in the opposite
direction
- E.F. Schumacher |
|
And simple truth miscalled simplicity,
- W. Shakespeare (Sonnet 66) |
|
Learning results from what the student does and thinks, and only from what
the student does and thinks.
The teacher can advance learning only by influencing the student to learn.
- H. Simon |
|
Mathematics is a language.
We want scientists to be able to read it, speak it, and write it.
But we are are not training them to be grammarians.
- H. Simon |
|
I'd rather write programs to write programs than write programs.
- D. Sites |
|
I cannot teach anybody anything, I can only make them think.
- Socrates |
|
One must learn by doing the thing; for though you think you know it, you have
no certainty, until you try.
- Sophocles |
|
Computers do not solve problems -computers carry out solutions, specified by
people, to problems.
- D. D. Spencer |
|
EMACS could not have been reached by a process of careful design, because such
processes arrive only at goals which are visible at the outset, and whose
desirability is established on the bottom line at the outset.
Neither I nor anyone else visualized an extensible editor until I had made one,
nor appreciated its value until he had experienced it.
EMACS exists because I felt free to make individually useful small
improvements on a path whose end was not in sight.
- R. Stallman |
|
Giving the Linus Torvalds Award to the Free Software Foundation is a bit like
giving the Han Solo Award to the Rebel Alliance.
- R. Stallman |
|
Being forced to write comments actually improves code, because it is easier to
fix a crock than to explain it.
- G. Steele |
|
[teaching]is rather artificial.
The world is complicated and messy, with lots of loose ends, and the teacher's
job is to impose order on the confusion, to convert a chaotic set of
episodes into a coherent narrative.
- I. Stewart (in "Letters to a Young Mathematician") |
|
Don't get suckered in by the comments -they can be terribly misleading: Debug
only the code.
- D. Storer |
|
Design and programming are human activities; forget that and all is lost.
- B. Stroustrup |
|
It is my firm belief that all successful languages are grown and not merely
designed from first principles
- B. Stroustrup (in "The Design and Evolution of C++") |
|
More good code has been written in languages denounced as "bad" than in
languages proclaimed "wonderful" -much more.
- B. Stroustrup (in The Design and Evolution of C++) |
|
The most important single aspect of software development is to be clear about
what you are trying to build.
- B. Stroustrup |
|
There are only two kinds of programming languages: those people always bitch
about and those nobody uses.
- B. Stroustrup |
|
I have learned throughout my life as a composer chiefly through my mistakes
and pursuits of false assumptions, not my exposure to founts of wisdom
and knowledge.
- I. Stravinsky |
|
Omit needless words.
Vigorous writing is concise.
A sentence should contain no unnecessary words, a paragraph no unnecessary
sentences, for the same reason that a drawing should have no unnecessary
lines and a machine no unnecessary parts.
- W Strunk Jr (in The Elements of Style) |
|
Rewrite and revise.
Do not be afraid to seize what you have and cut it to ribbons ...
Good writing means good revising.
- W Strunk Jr (in The Elements of Style) |
|
In engineering, as in other creative arts, we must learn to do analysis to
support our efforts in synthesis.
One cannot build a beautiful and functional bridge without a knowledge of steel
and dirt, and a considerable mathematical technique for using this knowledge
to compute the properties of structures.
Similarly, one cannot build a beautiful computer system without a deep
understanding of how to "previsualize" the process generated by the code one
writes.
- G. Sussman |
|
It is a bad plan that admits of no modification.
- P. Syrus |
|
Once you succeed in writing the programs for [these] complicated algorithms,
they usually run extremely fast.
The computer doesn't need to understand the algorithm, its task is only to run
the programs.
- R. Tarjan |
|
A programming language is a system of notation for describing computations.
A useful programming language must therefore be suited for both
description(i.e., for human writers and readers of programs) and for
computation (i.e., for efficient implementation on computers).
But human beings and computers are so different that it is difficult to find
notational devices that are well suited to the capabilities of both.
- R. Tennant (Principles of Programming Languages, Prentice Hall, 1981) |
|
The function of genius is not to give new answers, but to pose new questions
which time and mediocrity can resolve.
- H. Trevor-Howard |
|
It is better to have an approximate answer to the right question than an exact
answer to the wrong one.
- J. Tukey |
|
Unless in communicating with it [a computer] one says exactly what one means,
trouble is bound to result.
- A. Turing |
|
We shall do a much better programming job, provided we approach the task with a
full appreciation of its tremendous difficulty, provided that we respect the
intrinsic limitations of the human mind and approach the task as very humble
programmers.
- A. Turing |
|
He [John von Neumann] had the invaluable faculty of being able to take the
most difficult problem and separate it into its components, whereupon
everything looked brlliantly simple.
- S. Ulam (Bull. of American Mathematical Society, May 1958) |
|
It's easy to cry "bug" when the truth is that you've got a complex system and
sometimes it takes a while to get all the components to co-exist peacefully.
- D. Vargas |
|
The outcome of any serious research can only be to make two questions grow
where only one grew before.
- T. Veblen |
|
The best is the enemy of the good.
- Voltaire ("Dramatic Art" in _Philosophical Dictionary, 1764) |
|
Judge a man by his questions, rather than his answers.
- Voltaire |
|
The problem with using C++... is that there's already a strong tendancy in the
language to require you to know everything before you can do anything.
- L. Wall |
|
The mediocre teacher tells.
The good teacher explains.
The superior teacher demonstrates.
The great teacher inspires.
- W. A. Ward |
|
I think there is a world market for maybe five computers.
- T. J. Watson (Founder and Chairman, IBM), 1943 |
|
If you want to increase your success rate, double your failure rate.
- T. J. Watson |
|
The best writing is rewriting.
- E. B. White |
|
By relieving the brain of all unnecessary work, a good notation sets it free
to concentrate on more advanced problems, and in effect increases the mental
power of the race.
- A. N. Whitehead |
|
It is a profoundly erroneous truism, repeated by all the copybooks, and by
eminent people when they are making speeches, that we should cultivate the
habit of thinking what we are doing.
The precise opposite is the case.
Civilization advances by extending the number of operations which we
can perform without thinking about them.
Operations of thought are like cavalry charges in a battle -they are strictly
limited in number, they require fresh horses, and must only be made at
decisive moments.
- A. N. Whitehead (in "An Introduction to Mathematics") |
|
The computer programmer ... is a creator of universes for which he alone
is the lawgiver ...
universes of virtually unlimited complexity can be created in the form
of computer programs.
Moreover ... systems so formulated and elaborated act out
their programmed scripts.
They compliantly obey their laws and vividly exhibit their obedient behavior.
No playwright, no stage director, no emperor, however powerful, has ever
exercised such absolute authority to arrange a stage or a field of battle
and to command such unswervingly dutiful actors or troops.
- J. Weizenbaum (Computer Power and Human Reason, page 115) |
|
Newton was a genius, but not because of the superior computational power of his
brain.
Newton's genius was, on the contrary, his ability to simplify, idealize, and
streamline the world so that it became, in some measure, tractable to the
brains of perfectly ordinary men.
- G. M. Weinberg |
|
I have never learned anything except from people younger than myself.
- O. Wilde |
|
As soon as we started programming, we found out to our surprise that it wasn't
as easy to get programs right as we had thought.
Debugging had to be discovered.
I can remember the exact instant when I realized that a large part of my life
from then on was going to be spent in finding mistakes in my own programs.
- M. Wilkes |
|
Furious activity is no substitute for understanding.
- H. H. Williams |
|
From a programmer's point of view, the user is a peripheral
that types when you issue a read request.
- P. Williams |
|
He knows the course forwards and backwards. He teaches it backwards
- S. Willoughby
(commenting on Garrett Birkhoff's freshman calculus course at Harvard |
|
Complexity has and will maintain a strong fascination for many people.
It is true that we live in a complex world and strive to solve inherently
complex problems, which often do require complex mechanisms.
However, this should not diminish our desire for elegant solutions, which
convince by their clarity and effectiveness.
Simple, elegant solutions are more effective, but they are harder to find
than complex ones, and they require more time, which we too often believe
to be unaffordable
- N. Wirth |
|
Increasingly, people seem to misinterpret complexity as sophistication, which
is baffling -the incomprehensible should cause suspicion rather than
admiration.
Possibly this trend results from a mistaken belief that using a somewhat
mysterious device confers an aura of power on the user.
- N. Wirth |
|
Software gets slower faster than hardware gets faster.
(Or, sometimes known by] Grove [the head of Intel] giveth and
Gates [the head of Microsoft] taketh away.)
- N. Wirth |
|
Don't ask what it means, but rather how it is used.
- L. Wittgenstein |
|
If we spoke a different language, we would perceive a somewhat different
world.
- L.
- L. Wittgenstein |
|
More bugs have been introduced into programs through premature optimization
than any other cause, including pure stupidity.
(sometimes quoted as, "More computing sins are committed in the name of
efficiency (without necessarily achieving it) than for any other single
reason -including blind stupidity.")
- W. Wulf |
|
Education is not the filling of a pail, but the lighting of a fire.
- W.B. Yeats (See Plutarch: The mind...) |
|
Cutler, armed with a schedule [for finishing MS Windows NT], was urging
the tream to "eat its own dog food."
Part macho stunt and part common sense, the "dog food diet" was the cornerstone
of Cutler's philosophy.
"We're going to run on the program we build," he insisted.
Eating dog food meant there would be no escape from facing the flaws and
imperfections of NT.
Even while immersed in his own piece of NT, a code writer would confront all
of its weaknesses.
By controlling the operations of a code writer's computer, NT would define
the quality of his life.
If at first NT tasted no better than dog food, all the better.
Code writers would feel an urgent need to raise the dietary level by quickly
fixing the errant code and writing more durable code in the first place.
- G. P. Zachary (in "Show-Stopper: The Breakneck Race to Create Windows NT and the Next Generation at Microsoft") |
|
Technical skill is mastery of complexity, while creativity is mastery of
simplicity.
- E. C. Zeeman |
|
One day Chao-Chou fell down in the snow, and called out: "Help me! Help
Me!"
A monk came and lay down beside him.
Chao-Chou got up and went away.
- Zen koan |
|
Who is wise? He who learns from all people...as it is said: "From all my
teachers I gained understanding".
- B. Zoma (Psalms 119:99) |
Thanks to the following contributors of quotes I've missed and felt worthy of appearing here, or of digging up the right attribution for quotes that I once listed as anonymous: Joel Adams, Jerry B. Altzman, Caroline Bauer, David Bell, Teresa Carrigan, David Edelheit, Sarah Fix, Rick Gee, Hakon (see his SoftwareQuotes.com web site), John Harrison, Herbert Holland, Randy Howe (see his book The Quotable Teacher, The Lyons Press, 2003), Jim Huggins (see his Short Quotes web site), Dalton Hunkins, David Kay, Pekka Kilpelainen, Jiajun Lim, Chris Lowell, Ben Mauer, Sean McLaughlin, Mary-Alice Muraski, Brad Osgood, Robert Noonan, Nick Parlante Dan Resler, Niseeth Sharma, Jonathan Shelly, Eugene Wallingford, Richard D. Zakia (see his Quotes for Teachers web site), the Lambda the Ultimate web site, the quoteland.com web site, the Andy "Krazy" Glew's Favorite Quotes and Sayings web site, the Bumper-Sticker Computer Science web site, a Programming Quotations web site, the sysprog.net Quotations for Programmers web site, the Alan Perlis Epigrams in Programming web site, the Paul Graham's Quotes (mostly about Lisp) web site, the Quotations on simplicity in software design web site, Programming Quotations web site, Eugene Fink's web site, Glenn Vanderburg: Quotations on Software Design web site, Glenn Vanderburg: Quotations on Software Design web site, jbox.dk Quotations on simplicity in software design web site. Mathematical and Educational Quotation Server at Westfield State College Quotations Related to University Studies of Computer Science (some in Finnish)