Tautology

   No one with credibility has challenged the prevailing view.
   Therefore, the prevailing view is correct.
   But no one who challenges the prevailing view is deemed credible.
  
   Belief without thought endangers freedom

   Tautology, from the Greek meaning "same words," is a redundancy by needless repetition. The strategy is often used by speakers to establish a position or present an argument or idea in a way that is true in and of itself. That is, one says the same thing twice using different words, using the different words to "prove" the validity of the first set of words.
   Here's an example: "It is audible to the ear." (How else would it be audible?)
   Here's another: "This premise must be valid because the concepts it contains are true." True and valid are synonyms, and neither proves the validity or truth of the premise.


   But the most dangerous use of a tautology is outlined in the opening sentences of this posting. If anyone who challenges the accepted wisdom or the prevailing view is dismissed as a crank not having credibility, this only strengthens the prevailing view. Far better that the challenge is not ignored, but its argument evaluated and discussed. Only then can the challenge be legitimately dismissed.

   Remember, Galileo was charged with heresy for teaching the heliocentric relationship of the sun and planets. But he was right.