"Our empirical criterion for a series of theories is that it should produce new facts. The idea of growth and the concept of empirical character are soldered into one."

“For centuries knowledge meant proven knowledge... Einstein's results again turned the tables and now very few philosophers or scientists still think that scientific knowledge is, or can be, proven knowledge. But few realize that with this the whole classical structure of intellectual values falls in ruins and has to be replaced.”

“T' explains the previous success of T, that is, all the unrefuted content of T is included in the content of T'; and”

“Where theory lags behind the facts, we are dealing with miserable degenerating research programmes.”

“Kuhn as does Popper rejects the idea that science grows by accumulation of eternal truths.. But while according to Popper science is ‘revolution in permanence’, and criticism the heart of the scientific enterprise, according to Kuhn revolution is exceptional and, indeed, extra-scientific, and criticism is, in ‘normal’ times, anathema... The clash between Popper and Kuhn is not about a mere technical point in epistemology. It concerns our central intellectual values, and has implications not only for theoretical physics but also for the underdeveloped social sciences and even for moral and political philosophy. If even in science there is no other way of judging a theory but by assessing the number, faith and vocal energy of its supporters, then this must be even more so in the social sciences: truth lies in power. Thus Kuhn’s position would vindicate, no doubt, unintentionally, the basic political credo of contemporary religious maniacs .”

“T' has excess empirical content over T: that is, it predicts novel facts, that is, facts improbable in the light of, or even forbidden, by T;”

“It would be wrong to assume that one must stay with a research programme until it has exhausted all its heuristic power, that one must not introduce a rival programme before everybody agrees that the point of degeneration has probably been reached.”