"When popular opinion is nearly unanimous, contrary thinking tends to be most profitable. The reason is
that once the crowd takes a position, it creates a short-term, self-fulfilling prophecy.
But when a change occurs, everyone seems to change his mind at once."

"The crowd never thirsted for the truth."
both: Gustave Le Bon
The Crowd: A Study of the Popular Mind

"Sometimes the noisy handful is right, sometimes wrong; but no matter, the crowd follows it."
Mark Twain 

"Once we are in action, tactical aspects tend to be overriding, while the strategic framework tends to be forgotten."
Henry Kissinger

"Risk means that more things can happen than will happen."
Elroy Dimson

"We have only one sample of the past."
Paul Samuelson

"In a world as crazy as this one, it ought to be easy to find something
that happens solely by chance. It isn't."
Kevin McKeen
The Orderly Pursuit of Pure Disorder, Discover, January, 1981

"The real trouble with the world of ours is not that it is an
unreasonable world, nor even that it is a reasonable one.
The commonest kind of trouble is that it is nearly reasonable,
but not quite. Life is not an illogicality; yet it is a trap for logicians.
It looks just a little more mathematical and regular than it is.
Its exactitude is obvious, but its inexactitude is hidden; its wildness lies in wait."
G. K. Chesterton

"The greater danger of most of us is not that our aim is too high and we miss it,
but that it's too low and we reach it."
Michelangelo

"Simple is not easy."
unknown origin

"If you don't know who you are, the stock market is an expensive place to find out."
George Goodman

"It is impossible to predict news events-the stone hitting the water - 
but by modeling the structure of the markets it is possible to predict how
the ripples will pass through the lake and cause secondary reactions."
Richard Olsen, CEO Olsen Group

"Analysts are historians, who are predicting the past."
Craig R. Barrett, CEO Intel

"Going against the consensus is the way an analyst makes his or her mark."
Steven Garmaise, Midland Walwyn Capital

"Capitalism without bankruptcy is like Christianity without hell."
Frank Bormann, CEO, Eastern Airlines, 1986

"If a man will begin with certainties, he shall end in doubts,
but if he will be content to begin with doubts, he shall end in certainties."
Francis Bacon

"From time to time we should examine the criterion upon which we base our judgments."
Mahatma Gandhi

"I Hear, I Forget
I See, I Remember
I Do, I Understand."
Chinese Proverb

"Live (markets) can only understood backwards, but it (they) must be lived (traded) forward."
Sören Kierkegaard, Danish Philosopher

"Progress in knowledge results more from efforts to find faults with our theories, rather than prove them."
Sir Karl Popper, Austrian Philosopher

"The opposite of a correct statement is a false statement.
 But the opposite of a profound truth may well be another profound truth."
Niels Bohr, Atomic Physics and Human Knowledge

"Everything should be made as simple as possible, but not any simpler."
Albert Einstein

"There is nothing so disastrous as a rational investment policy* in an irrational world."
John Maynard Keynes
Maybe he is right but I prefer a rational investment policy rather than an emotional one.*