The Structure of Scientific Revolutions by Thomas S. Kuhn

• If science is the constellation of facts, theories, and methods collected in curent texts, then scientists are the men who, successfully or not, have striven to contribute one or another element to that particular constellation. Scientific development becomes the piecemeal process by which these items have been added, singly and in combination, to the ever growing stockpile that constitutes scientific techniques and knowledge. And history of science becomes the discipline that chronicles both these successive increments and the obstacles that have inhibited their accumulation.
• Observation and experience can and must drastically restrict the range of admissible scientific belief, else there would be no science.
• To be accepted as a paradigm, a theory must seem better than it competitors, but it need not, and in fact never does, explain all the facts with which it can be confronted.
• Paradigms gain their status because they are more successful than their competitors in solving a few problems that the group of practitioners has come to recognize as acute. To be more successful is not, however, to be either complexity successful with a single problem or notably successful with any large number.
• On the contrary, the process of learning a theory depends upon the study of application, including practice problems-solving both with a pencil and paper and with instruments in the laboratory.
• Philosophers of science have repeatedly demonstrated that more than one theoretical construction can always be placed upon a given collection of data. History of science indicates that, particularly in the early developmental stages of a new paradigm, it is not even very difficult to invent such alternatives. But that invention of alternates is just what scientists seldom undertake except during the pre-paradigm stage of their science’s development and at very special occasions during its subsequent evolution.
• The transition from a paradigm in crisis to a new one from which a new tradition of normal science can emerge is far from a cumulative process, one achieved by an articulation or extension of the old paradigm. Rather it is a reconstruction of the field from new fundamentals, a reconstruction that changes some of the fields’ most elementary theoretical generalizations as well as many of its paradigm methods and applications.
• During the transition period there will be large but never complete overlap between the problems that can be solved by the old and by the new paradigm.
• Einstein’s theory can be accepted only with the recognition that Newton’s was wrong.
• The temptation to write history backward is both omnipresent and perennial. But scientists are more affected by the temptation to rewrite history, partly because the results of scientific research show no obvious dependence upon the historical context of the inquiry, and partly because, except during crisis and revolution, the scientist's contemporary position seems so secure.
• Probably the single most prevalent claim advanced by the proponents of a new paradigm is that they can solve the problems that have led the old one to a crisis. When it can legitimately be made, this claim is often the most effective one possible.
• One of the strongest, if still unwritten, rules of scientific life is the prohibition of appeals to head of state or to the populace at large in matters scientific.