A man must love the thing very much if he not only practices it without any hope of fame or money, but even practices it without any hope of doing it well.
--G.K. Chesterton
It is plain that we exist for our fellow men -- in the first place for those upon whose smiles and welfare our happiness depends, and next for all those unknown to us personally but to whose destinies we are bound by the tie of sympathy.
--Albert Einstein
If you want to be happy, be.
--Kozma Prutkov

suum cuique
--to each one his own
If a problem has no solution, it's not a problem, it's a fact. Accept it.
-- Henry Kissinger (?)
Si j'avais la folie de croire en bonheur, je le chercherais dans l'habitude.
... the difference between ignorant and educated people is that the latter know more facts. But that has nothing to do with the fact whether they are stupid or intelligent. The difference between stupid and intelligent people---and this is true whether or not they are well-educated---is that intelligent people can handle subtlety. They are not baffled by ambiguous or even contradictory situations---in fact, they expect them and are apt to become suspicious when things seem overly straightforward.
--Neal Stephenson

Mathematicians, that find out, settle and do all the business, must content themselves with being nothing but dry calculators and drudges, and another that does nothing but pretend and grasp at all things must carry away all the inventions as well of those that were to follow him as of those that went before... And... I must now acknowledge in print I had all from him and so did nothing myself but drudge in calculating, demonstrating and writing upon the inventions of the great man.
--Isaak Newton of Robert Hooke
...My Dear Sir -- I received your paper, and thank you very much for it. I do not say I venture to thank you for what you have said about "Lines of Force," because I know you have done it for the interests of philosophical truth; but you must suppose it is work grateful to me, and gives me much encouragement to think on. I was at first almost frightened when I saw such mathematical force made to bear upon the subject, and then wondered to see that the subject stood it so well.
--Michael Faraday, in a letter to Maxwell 

"But still, imagine that you are God..."
Budah laughed.
"If I could imagine myself a god, I would become one!"
"Well, what if you could advise God?"
"You have a rich imagination," Budah said contentedly. "That's good. Are you literate? Excellent! I would love to tutor you..." "You flatter me... But still, what would you advise the Almighty? What, in your opinion, should the Omnipotent do so that you would say: Now the world is good and kind?"
Budah, smiling approvingly, leaned back and crossed his hands on his belly. Kira looked at him hungrily.
"Well," he said, "here's what I would do. I would tell the Lord: 'Creator, I do not know your plans, perhaps you have no intention of making people good and happy. Choose to wish this! It is so easily achieved! Give people enough bread, meat and wine, give them shelter and clothing. Let hunger and need disappear, and with them everything that separates people.'"
"And that's it?" asked Rumata.
"You think that is not enough?"
Rumata shook his head. "God would answer:
'This would not benefit people. For the strong of the world will take from the weak what I have given them, and the weak still will be destitute.'"
"I would ask God to protect the weak. 'Admonish the cruel rulers,' I would say."
"Cruelty is power. Without cruelty, the rulers will lose their power, and other cruel ones will take over."
Budah stopped smiling.
"Punish the cruel ones," he said firmly, "so the strong ones would not dare to be cruel to the weak."
"Man is born weak. He becomes strong when there is nobody around stronger than him. When the cruel among the strong are punished, their place will be taken by the stronger among the weak. Also cruel. In this way one would have to punish everybody, and I do not want that."
"You know best, o Lord. Then simply make it so that people have everything and do not take from each other what you have given them."
"This will not benefit people either," sighed Rumata, "for when they get everything for free, without effort, from my hands, they will forget work, will lose the taste of life and will become my domestic animals, whom I will then have to feed and clothe forever."
"Do not give them everything at once!" said Budah hotly. "Give them a little at a time, gradually!"
"Gradually people themselves will take all that they will need."
Budah laughed awkwardly.
"Yes, I see this in not so simple," he said. "Somehow I have never considered these matters. It seems we have run out of ideas. However," he leaned forward, "here is one more possibility. Make it so that all people love work and knowledge the most, so that work and knowledge became the only purpose in their lives!"
Yes, we were planning to do this, too, thought Rumata. Mass hypnoinduction, positive remoralization. Hypnoradiators on the three equatorial satellites...
"I could do that," he said. "But is it worth it to deprive the human race of its history? Is it worth it to substitute this humanity by another one? Would it not be the same thing as erasing this humanity from the face of the Earth and creating a new one in its place?"
Budah considered this silently. Rumata waited. Outside the window, the carriages were squeaking gloomily. Budah said quietly:
"Then, o Lord, erase us from the face of this Earth and create again, more perfect. Or better still, let us be and choose our own way."
"My heart is full of pity," said Rumata slowly. "I cannot do that."
--A. & B. Strugatskii, It's Hard to Be a God
The Royal Mathematician was a bald-headed, nearsighted man, with a skullcap on his head and a pencil behind each ear. He wore a black suit with white numbers on it. "I don't want to hear a long list of all the things you have figured for me since 1907," the King said to him. "I want you to figure out right now how to get the moon for the Princess Lenore. When she gets the moon, she will be well again." "I am glad you mentioned all the things I have figured out for you since 1907," said the Royal Mathematician. "It so happens that I have a list of them with me."
--J. Thurber, Many Moons
A man must love the thing very much if he not only practices it without any hope of fame or money, but even practices it without any hope of doing it well.
--G.K. Chesterton
God is not willing to do everything, and thus take away our free will and that share of glory which belongs to us.
--N. Machiavelli
Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason.
--Sir John Harington
Very few things happen at the right time, and the rest do not happen at all. The conscientious historian will correct this defect.
--Herodotus (450 B.C)

I doubt not that such a nucleus-school would, with the growth of this active and knowledge-seeking community, finally expand into a great institution comprehending the whole field of physical science and the arts with the auxiliary branches of mathematics and modern languages, and would soon overtop the universities of the land in the accuracy and the extent of its teaching in all branches of positive knowledge
When thus instructed in applied science, the mechanician, chemist, manufacturer or engineer clearly comprehends the agencies of the materials and instruments with which he works, and is, therefore, saved from the disasters of blind experiment, is guided securely because understandingly in a profitable routine, and is directed in the contrivance of new and more combinations.
--William Rogers (founder of MIT), 1846, first set down his ideas for a polytechnic institution

From a drop of water a logician could infer the possibility of Atlantic or a Niagara without having seen or heard of one or the other.
--Sherlock Holmes, A Study in Scarlet
An insanity as enormous, as complex, as the one around me had to be planned.
--R. Heinlein, They
And at the end of our exploring

Will be to arrive where we started
And know the place for the first time.
--T.S. Eliot, Little Gidding
If you don't make mistakes, you're not working on hard enough problems. And that's a big mistake.
--F. Wilczek, unsolicited advice to graduate students
I consider that I understand an equation when I can predict the properties of its solutions, without actually solving it.
--P.A.M. Dirac
We came less and less to require that Love should be enthroned behind the stars; more and more we desired merely to pass on, opening our hearts to accept fearlessly whatever of the truth might fall within our comprehension.
--O. Stapledon, Starmaker

Two complementary stories:

A certain boy once drew a beautiful, if somewhat abstract picture. He was asked: "And what did you mean to say by this?" To which he replied, "I meant exactly what I said."

A boy (perhaps the same one) was taken to a museum and shown an abstract picture. The guide explained: "This is meant to be a horse." To which the boy replied, "If it is meant to be a horse, why isn't it a horse?"

Many have noted that the process of transformation of a hypothesis into a scientific discovery can be illustrated very well by the example of Columbus's discovery of America. Columbus was obsessed with the idea that the Earth was round and one could reach East Indies sailing West.

Note the following:
  1. The idea was by no means original, but he obtained new information
  2. He experienced great difficulties in the search for sponsors as well as in the performance of the experiment itself
  3. He did not find a new way to India, but he found a new world
  4. Despite all the evidence to the contrary, he still believed he had found the way to the East
  5. In his lifetime he received neither great respect nor a significant reward
  6. Since then irrefutable evidence was found that Columbus was not the first European to reach America
...One of the major reasons for the overwhelming current of scientific literature is the fact that when a researcher reaches the stage when he stops seeing the forest behind the trees he is too readily inclined to solving this problem by switching to the study of individual leaves.
The rule of the thirteenth stroke, which one should remember when reading a paper that promises too much: if a clock strikes thirteen times, it does not mean that the thirteenth stroke was wrong. It produces doubts as to the correctness of each of the first twelve strokes.
--John Masters

It is plain that we exist for our fellow men -- in the first place for those upon whose smiles and welfare our happiness depends, and next for all those unknown to us personally but to whose destinies we are bound by the tie of sympathy.
--Albert Einstein
To be a leader of men one must turn one's back on men.
--H. Ellis

Various quotes stolen from peoples' signature files.

I came into this world, not chiefly to make this a good place to live in but to live in it, be it good or bad.
Fire is the most tolerable third party
To be awake is to be alive
The works of the great poets have never yet been read by mankind, for only great poets can read them.
--H.D. Thoreau 

It is a bad plan that admits no modification
Every day should be passed as if it were our last.
Everything is worth what its purchaser will pay for it.
--Publitius Syrus
No man can enjoy happiness without thinking that he enjoys it
--S. Johnson
Should you read, upon an enclosure with an elephant, a sign saying Buffalo, believe not your eyes.
If you want to be happy, be.
--Kozma Prutkov
Do not seek to follow in the footsteps of the men of old; seek what they sought
--Matsuo Basho
On mourra seul
"The God of Abraham, the God of Isaac, the God of Jacob," not of philosophers and scholars.
--B. Pascal
Dear Lord, give me chastity and self-restraint ... but not yet, O Lord, not yet!
--Saint Augustine, A.D. 354-430
Success is a journey, not a destination.
--Ben Sweetland
Long range planning does not deal with future decisions, but with the future of present decisions
--Peter Drucker
It takes twenty years to make an overnight success.
--Eddie Cantor
Even if you are on the right track, you'll get run over if you just sit there
--Will Rogers
Software rot, noun -- a hypothetical disease the existence of which has been deduced from the observation that unused programs or features will stop working after sufficient time has passed, even if nothing has changed.
--the Devil's Dictionary
To err is human, but when the eraser wears out ahead of the pencil, you're overdoing it.
--J. Jenkins
Two things, well considered, would prevent many quarrels; first, to have it well ascertained whether we are not disputing about terms rather than things; and secondly, to examine whether that on which we differ is worth contending about.
If you think the cost of education is high, think about ignorance.
--Derek Bok, president of Harvard University
The Second Law of Marketing: The best way to get clients is to have clients
Prescott's Pickle Principle: Cucumbers get more pickled than brine gets cucumbered.
Anyone can predict the future, but the future doesn't have to listen.
Testing against a specification is like walking on water - it helps if it is frozen.
The bitterness of poor quality is remembered long after the sweetness of meeting a deadline is forgotten.
My interest is in the future because I am going to spend the rest of my life there.
--Charles F. Kettering
It's easier to play the game when you know all the rules.
Don't verb nouns
--William Safire