The probable is what usually happens.

Bertrand, Joseph
Calcul des probabilités
How dare we speak of the laws of chance? Is not chance the antithesis of all law?

Boethius (ca. 480-525)
The Consolation of Philosophy
Chance, too, which seems to rush along with slack reins, is bridled and governed by law.

Boole, George
An Investigation of the Law of Thought
Probability is expectation founded upon partial knowledge. A perfect acquaintance with all the circumstances affecting the occurrence of an event would change expectation into certainty, and leave neither room nor demand for a theory of probabilities.

Born, Max
The conception of chance enters in the very first steps of scientific activity in virtue of the fact that no observation is absolutely correct. I think chance is a more fundamental conception that causality; for whether in a concrete case, a cause-effect relation holds or not can only be judged by applying the laws of chance to the observation.

Bulwer, Lytton E.G.
Eugene Aram
Fate laughs at probabilities.

Cardano, Girolamo
De Vita Propria Liber
To throw in a fair game of Hazards only three-spots, when something great is at stake, or some business is the hazard, is a natural occurrence and deserves to be so deemed, and even when they come up the same way for a second time if the throw be repeated. If the third and fourth plays are the same, surely there is occasion for suspicion on the part of a prudent man.

Caesar, Julius
Iacta alea est. (The die is cast.)

Christie, Agatha
The Mirror Crack'd
``I think you're begging the question,'' said Haydock, ``and I can see looming ahead one of those terrible exercises in probability where six men have white hats and six men have black hats and you have to work it out by mathematics how likely it is that the hats will get mixed up and in what proportion. If you start thinking about things like that, you would go round the bend. Let me assure you of that!''

Probability is the very guide of life.

Coolidge, Julian Lowell
In H. Eves, Return to Mathematical Circles
[Upon proving that the best betting stragegy for Gambler's Ruin was to bet all on the first trial.] It is true that a man who does this is a fool. I have only proved that a man who does anything else is an even bigger fool.

Davis, Philip and Hersh, Reuben
The Mathematical Experience
How many really basic mathematical objects are there? One is surely the `miraculous' jar of the positive integers 1, 2, 3 . . . Another is the concept of a fair coin. Though gambling was rife in the ancient world and although prominent Greeks and Romans sacrificed to Tyche, the goddess of luck, her coin did not arrive on the mathematical scene until the Renaissance. Perhaps one of the things that had delayed this was a metaphysical position which held that God speaks to humans through the action of chance. . . . The modern theory begins with the expulsion of Tyche from the Pantheon. There emerges the vision of the fair coin, the biased coin. This coin exists in some mental universe and all modern writers on probability theory have access to it. They toss it regularly and they speculate about what they 'observe.'"

Everything existing in the universe is the fruit of chance.

Discourse on Method
It is a truth very certain that when it is not in our power to determine what is true we ought to follow what is most probable.

Doob, J.
Quoted in Statistical Science
While writing my book [Stochastic Processes] I had an argument with Feller. He asserted that everyone said ``random variable'' and I asserted that everyone said ``chance variable.'' We obviously had to use the same name in our books, so we decided the issue by a stochastic procedure. That is, we tossed for it and he won.

Doyle, Sir Arther Conan
The Sign of Four
When you have eliminated the impossible, what ever remains, however improbable, must be the truth.

Einstein, Albert
I will never believe that god plays dice with the universe.

Feller, William
An Introduction to Probability Theory and its Applications
Probability is a mathematical discipline whose aims are akins to those, for example, of geometry of analytical mechanics. In each field we must carefully distinguish three aspects of the theory: (a) the formal logical content, (b) the intuitive background, and (c) the applications. The character, and the charm, of the whole structure cannot be appreciated without considering all three aspects in their proper relation.

An Introduction to Probability Theory and its Applications
All possible definitions of probability fall short of the actual practice.

Galton, Francis
The 'Law of Frequency of Error' . . . reigns with serentiy and in complete self-effacement amidst the wildest confusion. The huger the mob . . . the more perfrect is its sway. It is the supreme law of Unreason. Whenever a large sample of chaotic elements are taken in hand . . . an unsuspected and most beautiful form of regularity proves to have been latent all along.

Gay, John
Lest men suspect your tale untrue,
Keep probability in view.

Gould, Stephen Jay
Misunderstanding of probability may be the greatest of all impediments to scientific literacy.

Gould, Stephen Jay
Probability does pervade the universe, and in this sense, the old chestnut about baseball imitating life really has validity. The statistics of streaks and slumps, properly understood, do teach an important lesson about epistemology, and life in general. The history of a species, or any natural phenomenon, that requires unbroken continuity in a world of trouble, works like a batting streak. All are games of a gambler playing with a limited stake against a house with infinite resources. The gambler must eventually go bust. His aim can only be to stick around as long as possible, to have some fun while he's at it, and, if he happens to be a moral agent as well, to worry about staying the course with honor!

Kac, Mark
Enigmas of Chance
Steinhaus, with his predilection for metaphors, used to quote a Polish proverb, `Forturny kolem sie tocza' [Luck runs in circles], to explain why Pi, so intimately connected with circles, keeps cropping up in probability theory and statistics, the two disciplines which deal with randomness and luck.

Kolmogorov, Andrey
Foundations of the Theory of Probability
The theory of probability as a mathematical discipline can and should be developed from axioms in exactly the same way as geometry and algebra.

Laplace, Pierre Simon
Théorie Analytique des Probabilités, 1812
It is remarkable that a science which began with the consideration of games of chance should have become the most important object of human knowledge.

Théorie Analytique des Probabilités, 1812
The most important questions of life are indeed, for the most part, really only problems of probability.

Probability theory is nothing but common sense reduced to calculation.

L'Engle, Madeline
The world of science lives fairly comfortably with paradox. We know that light is a wave and also that light is a particle. The discoveries made in the infinitely small world of particle physics indicate randomness and chance, and I do not find it any more difficult to live with the paradox of a universe of randomness and chance and a universe of pattern and purpose than I do with light as a wave and light as a particle. Living with contradiction is nothing new to the human being.

Leucippus (5th century B.C.)
Nothing occurs at random, but everything for a reason and by necessity.

Maxwell, James Clerk
The actual science of logic is conversant at present only with things either certain, impossible, or entirely doubtful, none of which (fortunately) we have to reason on. Therefore the true logic for this world is the calculus of Probabilities, which takes account of the magnitude of the probability which is, or ought to be, in a reasonable man's mind.

Milton, John, Paradise Lost, I. 907
Chaos umpire sits,
And by decision more embroils the fray
By which he reigns: next him high arbiter
Chance governs all.

Nietzsche, Friedrich, Thus Spake Zarathustra
I say unto you: a man must have chaos yet within him to be able to give birth to a dancing star: I say unto you: ye have chaos yet within you . . .

Paley, William
What does chance ever do for us?

Pascal, Blaise
The excitement that a gambler feels when making a bet is equal to the amount he might win times the probability of winning it.

Pasteur, Louis
Chance favors the prepared mind.

Pearson, Karl
The record of a month's roulette playing at Monte Carlo can afford us material for discussing the foundations of knowledge.

Suam habet fortuna rationem. (Chance has its reasons.)

Pierce, Charles S.
Quoted in Mathematically Speaking
This branch of mathematics [Probability] is the only one, I believe, in which good writers frequently get results which are entirely erroneous.

I know too well that these arguments from probabilities are imposters, and unless great caution is observed in the use of them, they are apt to be deceptive.

Plum, Stephanie
Hard Eight
I graduated from Douglass College without distinction. I was in the top 98% of my class and damn glad to be there. I slept in the library and daydreamed my way through history lecture. I failed math twice, never fully grasping probability theory. I mean, first off, who cares if you pick a black ball or a white ball out of the bag? And second, if you're bent over about the color, don't leave it to chance. Look in the damn bag and pick the color you want.

Poe, Edgar Allen
Arsene Dupin, in The Murders in the Rue Morgue
Coincidences, in general, are great stumbling blocks in the way of that class of thinkers who have been educated to know nothing of the theory of probabilities---that theory to which the most glorious objects of human research are indebted for the most glorious of illustrations.

Rickey, Branch
Luck is the residue of design.

Twain, Mark
There are two times in a man's life when he should not speculate; when he can't afford it, and when he can.

von Neumann, John
Quote in Conic Sections by D. MacHale
Anyone who considers arithmetic methods of producing random digits is, of course, in a state of sin.

Wilde, Oscar
Always be a little improbable.

In a letter to Maurice Kendall
Isn't it extraordinary how difficult it is to get a sample really random? Every possible precaution, as it may seem, sometimes fails to protect one. I remember Greenwood telling me that, in some experiments done by drawing different coloured counters from a bag, there seemed to be a bias against one particular colour. On testing, they concluded that this colour had given the counters a slightly greasy surface, so that it tended to escape the sampler's fingers.