Thomas Kuhn

"What we call facts are actually the stable products of a paradigm at work."

"The scientist lives within a web of theoretical commitments that shape perception."

"Incommensurability means that different paradigms create different worlds of experience."

"The history of science shows that there is no view from nowhere."

"Science is not discovering a pre-existing reality, but constructing reality through practice."

"What we discover is shaped by the questions we ask and the tools we have."

"The scientist's commitment to a paradigm is rational, but not inevitable."

"Normal science is puzzle-solving within an accepted framework."

"Paradigm choice involves aesthetic and metaphysical considerations, not just logical ones."

"The future of science will be unrecognizable from our current vantage point."

"What seems rational is determined by the paradigm within which reason operates."

"The existence of paradigm debates is not really surprising, except for the fact that, throughout the history of the physical sciences, paradigm debates have again and again been resolved not by proof but by a gradually conversion of the entire profession."

"Discovery commences with the awareness of anomaly."

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

"We must learn to recognize the symptoms of dying paradigms."

"The man who makes no mistakes does not usually make anything."

"Copernicanism made few converts for almost a century after Copernicus. Why? In part because it was harder to use; extra circles were required to produce Ptolemaic accuracy."

"The decision to reject one paradigm is always simultaneously the decision to accept another."

"Crisis alone is not usually sufficient to induce the adoption of a new paradigm."

"What chemists took from Dalton was not new truth but a new group of puzzles and rules for solving them."

"The textbook of a past and obsolete scientific achievement, no longer alive as research."

"Scientific revolutions need not seem revolutions only after the fact."

"It is the failures of existing rules that create the puzzles for extraordinary science."

"We may, however, have to relinquish the notion that changes of paradigm carry scientists and those who learn from them closer and closer to the truth."

"No single author before the sixteenth century wrote a chemistry text."

"The success of a paradigm cannot be determined simply by the degree to which it solves the problems it was asked to solve."

"Each new theory, in some degree, emerges from the old, and must find ways to accommodate most of what went before."

"Nature's not easily caught in a net of words."

"Problems that cannot be solved within the existing paradigm may be very real problems."

"The crisis-to-revolution transition is not, however, something that can be made inevitable by any act of will."