I've always loved the initial exchange between Gregory and Syme in "The Man Who Was Thursday".

Context: Gregory is an anarchist poet, Syme is claiming to be a poet of respectability, which Gregory maintains is impossible.

....The poet delights in disorder only. If it were not so, the most poetical thing in the world would be the Underground Railway."

"So it is," said Mr. Syme.

"Nonsense!" said Gregory, who was very rational when anyone else attempted paradox. "Why do all the clerks and navvies in the railway trains look so sad and tired, so very sad and tired? I will tell you. It is because they know that the train is going right. It is because they know that whatever place they have taken a ticket for that place they will reach. It is because after they have passed Sloane Square they know that the next station must be Victoria, and nothing but Victoria. Oh, their wild rapture! oh, their eyes like stars and their souls again in Eden, if the next station were unaccountably Baker Street!"

"It is you who are unpoetical," replied the poet Syme. "If what you say of clerks is true, they can only be as prosaic as your poetry. The rare, strange thing is to hit the mark; the gross, obvious thing is to miss it. We feel it is epical when man with one wild arrow strikes a distant bird. Is it not also epical when man with one wild engine strikes a distant station? Chaos is dull; because in chaos the train might indeed go anywhere, to Baker Street or to Bagdad. But man is a magician, and his whole magic is in this, that he does say Victoria, and lo! it is Victoria. No, take your books of mere poetry and prose; let me read a time table, with tears of pride. Take your Byron, who commemorates the defeats of man; give me Bradshaw, who commemorates his victories. Give me Bradshaw, I say!"

This one should help you empathize with other people more.

"Everyone has a secret world inside of them. All the people in the whole world, no matter how dull they seem on the outside, inside them they've got unimaginable, magnificent, wonderful, stupid, amazing worlds."

-Neil Gaiman

The usual touchstone, whether that which someone asserts is merely his persuasion -- or at least his subjective conviction, that is, his firm belief -- is betting. It often happens that someone propounds his views with such positive and uncompromising assurance that he seems to have entirely set aside all thought of possible error. A bet disconcerts him. Sometimes it turns out that he has a conviction which can be estimated at a value of one ducat, but not of ten. For he is very willing to venture one ducat, but when it is a question of ten he becomes aware, as he had not previously been, that it may very well be that he is in error. If, in a given case, we represent ourselves as staking the happiness of our whole life, the triumphant tone of our judgment is greatly abated; we become extremely diffident, and discover for the first time that our belief does not reach so far. Thus pragmatic belief always exists in some specific degree, which, according to differences in the interests at stake, may be large or may be small. - Immanuel Kant , The Critique of Pure Reason

Meta: How is this supposed to be different from the existing rationality quotes thread?

It is easy to believe; doubting is more difficult. Experience and knowledge and thinking are necessary before we can doubt and question intelligently. Tell a child that Santa Claus comes down the chimney or a savage that thunder is the anger of the gods and the child and the savage will accept your statements until they acquire sufficient knowledge to cause them to demur. Millions in India passionately believe that the waters of the Ganges are holy, that snakes are deities in disguise, that it is as wrong to kill a cow as it is to kill a person - and, as for eating roast beef…that is no more to be thought of than cannibalism. They accept these absurdities, not because they have been proved, but because the suggestion has been deeply imbedded in their minds, and they have not the intelligence, the knowledge, the experience, necessary to question them. We smile…the poor benighted creatures! Yet you and I, if we examine the facts closely, will discover that the majority of our opinions, our most cherished beliefs, our creeds, the principles of conduct on which many of us base our very lives, are the result of suggestion, not reasoning… Prejudiced, biased, and reiterated assertions, not logic, have formulated our beliefs. - Dale Carnegie

The noble lord in this case, as in so many others, first destroys his opponent, and then destroys his own position afterwards. The noble lord is the Prince Rupert of parliamentary discussion: his charge is resistless, but when he returns from the pursuit he always finds his camp in the possession of the enemy.

Benjamin Disraeli, source, on the speeches of Lord Stanley. I often think of this quote regarding the effectiveness (or otherwise) of different kinds of rhetoric.

For context, Prince Rupert was a cavalry commander whose charges were extremely effective at shattering the opposing cavalry, but who was often unable to restrain his troops from going too far, and consequently lost a number of important battles in the English Civil War.

The same critical concept in two different disciplines:

"Of several responses made to the same situation, those which are accompanied or closely followed by satisfaction to the animal will, other things being equal, be more firmly connected with the situation, so that, when it recurs, they will be more likely to recur; those which are accompanied or closely followed by discomfort to the animal will, other things being equal, have their connections with that situation weakened, so that, when it recurs, they will be less likely to occur. The greater the satisfaction or discomfort, the greater the strengthening or weakening of the bond." - Edward Thorndike's Law of Effect, Animal Intelligence: Experimental Studies, 1911

"Public services are never better performed than when their reward comes in consequence of their being performed, and is proportioned to the diligence employed in performing them." - Adam Smith, The Wealth of Nations, 1776

Knowledge and productivity are like compound interest. Given two people of approximately the same ability and one person who works ten percent more than the other, the latter will more than twice outproduce the former. The more you know, the more you learn; the more you learn, the more you can do; the more you can do, the more the opportunity - it is very much like compound interest. I don't want to give you a rate, but it is a very high rate. Given two people with exactly the same ability, the one person who manages day in and day out to get in one more hour of thinking will be tremendously more productive over a lifetime.

-Richard Hamming, You and Your Research

Perhaps any sufficiently advanced logic is indistinguishable from stupidity. - Alex Tabarrok, The Rise of Opaque Intelligence