Kuhn, Thomas

"The paradigm is so deeply embedded that scientists are often unaware of its influence on their thinking."

"Scientific communities are not repositories of pure truth but of shared agreements about how to see the world."

"Crisis precedes and prompts revolutions; the awareness of malfunction is the beginning of discovery."

"The ability to see that something has gone wrong is the prerequisite for putting it right."

"Discovery commences with the awareness of anomaly."

"We are not accustomed to the idea that the observed world is not the one we were taught."

"The competition between paradigms is not the sort of battle that admits a decisive proof."

"What a man sees depends both upon what he looks at and also upon what his previous conceptual-perceptual experience has taught him to see."

"Normal science does not aim at novelties of fact or theory and, when successful, finds none."

"As in manufacture, so in science, retooling is an extravagance to be reserved for the occasion when another tool will wholly not do."

"The scientist who pauses to examine critically every major step of his procedure would quickly bring normal science to a stop."

"Perhaps science does not develop by the accumulation of individual discoveries and inventions."

"The historian constantly revises his interpretations of the past."

"Revolutionary changes in science need not destroy past achievements."

"No puzzle solved by science is ever fully solved. The only questions that science answers are ones that scientists ask."

"Textbooks thus begin by truncating the scientist's sense of his discipline's history."

"When the individual scientist is unsure which of several competing theories his field should pursue, he often opts for the one that promises the greatest intellectual satisfaction."

"Scientific revolutions need not involve objects that have changed. What must change is the scientist's conception of those objects."

"The success of a scientific theory often depends upon the ability to switch Gestalts in midstream."

"One of the things a scientific community acquires with a paradigm is a criterion for choosing problems that, while the paradigm is taken for granted, can be assumed to have solutions."

"Discovery of the unexpected is how science advances, yet also how paradigms shift."

"We may be able to discover much that the author did not intend or know when we read his work in a new way."

"The source of the confusion is that the two groups use the same words to talk about different things."

"Crisis alone is not enough; there must also be a basis, though it need not be rational, for choosing a new paradigm over an old one."

"The man who embraces dogma has ceased to be a scientist."

"Facts, when discovered, often emerge without warning as a result of careful empirical work."

"Scientists work from models acquired through education and through subsequent exposure to the literature often without quite knowing or needing to know what characteristics have given these models the status of community paradigms."

"I have tried to show what being wrong looks like in science."

"Awareness of anomaly opens a period in which conceptual categories are adjusted until the anomaly seems to go away."

"The developmental process described in this essay has been a process of evolution from primitive beginnings—a process whose successive stages appeared to modern eyes as evolutionary without being truly revolutionary."