There are a lot of ideas in science that persist, even in the face of little or no experimental support.  For instance, the famous chemist Linus Pauling, recipient of two Nobel Prizes, suggested in 1970 that large doses of vitamin C would ward off the common cold.  As a side benefit, he claimed that this vitamin would also help protect against cancer.

Perhaps because of his impressive credentials, Pauling’s claim was not dismissed out of hand by the medical profession.  Even though controlled experiments on the use of vitamin C did not substantiate his claims, Pauling added more diseases to his list that could be alleviated by vitamin C.  He even proposed mechanisms by which this vitamin works.  But further controlled experiments again failed to verify his claims.

But experimental evidence or not, we always have to factor in human nature.  I’m a chemist who knew and respected Pauling, who died not long ago in his 94th year.  And hey, I still take vitamin C!  You see, scientists are not always as rational as they claim.  When the famous Danish physicist Neils Bohr was asked whether he believed the horseshoe above his cottage door would bring him good luck, he replied, “No, but they say it works even if you don’t believe in it!”

So next time someone says scientists are always rational, remember the even the big names sometimes believe scientific heresy.