In degenerating programmes, however, theories are fabricated only in order to accommodate known facts.

Man's respect for knowledge is one of his most peculiar characteristics. Knowledge in Latin is scientia, and science came to be the name of the most ….

Belief may be a regrettably unavoidable biological weakness to be kept under the control of criticism: but commitment is for Popper an outright crime..

Indeed, this epistemological theory of the relation between theory and experiment differs sharply from the epistemological theory of naive falsificat….

It is not that we propose a theory and Nature may shout NO; rather, we propose a maze of theories, and Nature may shout INCONSISTENT..

There is no falsification before the emergence of a better theory..

Philosophy of science without history of science is empty; history of science without philosophy of science is blind..

Einstein's results again turned the tables and now very few philosophers or scientists still think that scientific knowledge is, or can be, proven kn….

That sometimes clear ... and sometimes vague stuff ... which is ... mathematics..

The classical example of a successful research programme is Newton's gravitational theory: possibly the most successful research programme ever..

The proving power of the intellect or the senses was questioned by the skeptics more than two thousand years ago; but they were browbeaten into confu….

The positive heuristic of the programme saves the scientist from becoming confused by the ocean of anomalies..

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 ….

The great scientific achievements are research programmes which can be evaluated in terms of progressive and degenerative problemshifts; and scientif….

Intellectual honesty consists in stating the precise conditions under which one will give up one's belief..

One may rationally stick to a degenerating research programme until it is overtaken by a rival and even after. What one must not do is to deny its po….

The history of mathematics, lacking the guidance of philosophy, [is] blind, while the philosophy of mathematics, turning its back on the most intrigu….

No experimental result can ever kill a theory: any theory can be saved from counterinstances either by some auxiliary hypothesis or by a suitable rei….

Mathematics does not grow through a monotonous increase of the number of indubitably established theorems but through the incessant improvement of gu….

If even in science there is no a way of judging a theory but by assessing the number, faith and vocal energy of its supporters, then this must be eve….

Blind commitment to a theory is not an intellectual virtue: it is an intellectual crime..