Individuals who break through by inventing a new paradigm are almost always either very young men or very new to the field whose paradigm they change….

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

Groups do not have experiences except insofar as all their members do. And there are no experiences... that all the members of a scientific community….

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