These are some quotes that I don't necessarily live by, but may have some application to something:

"There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact."
Mark Twain

"I know that most men, including those at ease with problems of the greatest complexity, can seldom accept even the simplest and most obvious truth if it be such as would oblige them to admit the falsity of conclusions which they have delighted in explaining to colleagues, which they have proudly taught to others, and which they have woven, thread by thread, into the fabric of their lives."
Leo Tolstoy

"The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' (I found it!) but 'That's funny ...'"
Isaac Asimov (1920 - 1992)

"I believe that a scientist looking at nonscientific problems is just as dumb as the next guy."
Richard Feynman (1918 - 1988)

"In science the credit goes to the man who convinces the world, not the man to whom the idea first occurs."
Sir Francis Darwin (1848 - 1925)

"The important thing in science is not so much to obtain new facts as to discover new ways of thinking about them."
Sir William Bragg (1862 - 1942)

"Whenever you find that you are on the side of the majority, it is time to reform."
Mark Twain

"Many a small thing has been made large by the right kind of advertising."
Mark Twain, A Connecticut Yankee in King Arthur's Court

"Contradictions do not exist. Whenever you think you are facing a contradiction, check your premises. You will find that one of them is wrong"
Ayn Rand