The way of science is paved with discarded theories which were once declared self-evident;

Science books go out of date. We throw the old one away when a newer one comes out, when we have new theories. But we don't throw away our old data; we merely interpret them differently. New theories try to account for old data (and new data) in new ways.

In the developed sciences, theories tend either to become widely accepted and built into the larger edifice of well-tested human knowledge or else they suffer destruction in the face of recalcitrant facts and are abandoned, perhaps regretfully as a “nice try.” But in fields like personology and social psychology, this seems not to happen. There is a period of enthusiasm about a new theory, a period of attempted application to several fact domains, a period of disillusionment as the negative data come in, a growing bafflement about inconsistent and unreplicable empirical results, multiple resort to ad hoc excuses, and then finally people just sort of lose interest in the thing and pursue other endeavors.

A theory which is not refutable by any conceivable event is nonscientific. Irrefutability is not a virtue of a theory (as people often think) but a vice.

You're quite right: that theory is taken a bit less seriously." "But it isn't discredited, is it?" "You can't discredit an untestable hypothesis.

a theory that has seven facts for it and three facts against it is not in good shape, and it would not be considered so in any developed science.

Many theories of the ancient world seem terribly childish today, a hodge-podge of fables and false comparisons.But our theories will seem childish five-hundred years from now.Every theory is based on some analogy, and sooner or later the theory fails because the analogy turns out to be false. A theory in its day helps to solve the problems of the day.

If you can’t think of an observation that could disprove a theory, that theory simply isn’t scientific.

older theories become more and more unclear when one tries to use them to obtain insight into new domains.

Conservatism, we are told, is out-of-date. This charge is preposterous and we ought to boldly say so. The laws of God, and of nature, have no dateline. […] These principles are derived from the nature of man, and from the truths that God has revealed about His creation. […] To suggest that the Conservative philosophy is out of date is akin to saying that the Golden Rule, or the Ten Commandments or Aristotle’s Politics are out of date.

The progress of science is strewn, like an ancient desert trail, with the bleached skeletons of discarded theories which once seemed to possess eternal life.

Scientific theories are distinguished from myths... in being criticizable, and... open to modifications... They can be neither verified nor probabilified.

If the fact will not fit the theory - let the theory go

Scientific theories need reconstruction every now and then. If they didn't need reconstruction they would be facts, not theories.