Fundamental Cause

The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.  Even those of the intelligent who believe that they have a nostrum are too individualistic to combine with other intelligent men from whom they differ on minor points.

-- Bertrand Russell (1872 - 1970), British philosopher and mathematician, 1950 Nobel Laureate in Literature, in his essay "The Triumph of Stupidity" (1933), lamenting the rise of the Nazi movement in Germany, h/t Quote Investigator