The first principle is that you must not fool yourself—and you are the easiest person to fool.

So you have to be very careful about that.

After you’ve not fooled yourself, it’s easy not to fool others. You just have to be honest in a conventional way after that.

Rich Feynman

One way in which a revolutionary scientific principle differs from the typical crank theory: No matter how widespread its implications, no matter how many previously accepted laws must be modified, all the changes fit into one thoroughly integrated pattern.

The scientist respects Nature and its laws insofar as they are already known.

The crank, on the other hand, has a theory that he seeks to force upon Nature, and he will ignore all facts and deny all theories that stand in his way.

The biological crank has the intrinsically harmless theory, for example, that there are winged elephants.

Where?

For convenience, let us say they are in the next room.

If we do not see them, then perhaps we have a curious physical fact, that light rays bend around winged elephants, thus making them invisible.

Or a curious psychological fact, that winged elephants are good hypnotists and hypnotically persuade us that they are not there.

Or perhaps a curious sociological fact, that all other men are engaged in a conspiracy to discredit the crank.

Laurence Lafleur, Cranks & Scientists

If a man persists in advancing views that are contradicted by all available evidence, and which offer no reasonable grounds for serious consideration, he will rightfully be dubbed a crank by his colleagues.

Martin Gardner, Fads & Fallacies

It is notorious in psychology, sociology, and anthropology that myths and legends are of dubious evidential value.

No matter how many individuals and nations believe in Santa Claus, the serious philosopher or scientist will demand better evidence before accepting the belief, and would never dream of opposing the evidence of legend to that of controlled observation and successful prediction.

Even when the same legend appears with many apparently independent origins, as in the case of the “magic flight,” we are not tempted to believe it.

Laurence Lafleur, Cranks & Scientists