“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.”

Often paraphrased as &quot;The whole problem with the world is that fools and fanatics are always so certain of themselves, but wiser people so full of doubts.&quot; <br class="br">Compare: &quot;One of the painful things about our time is that those who feel certainty are stupid, and those with any imagination and understanding are filled with doubt and indecision.&quot; B. Russell, New Hopes for a Changing World (1951). Compare also: &quot;The best lack all conviction, while the worst / Are full of passionate intensity.&quot; W. B. Yeats, The Second Coming (1919). <br class="br">See also: Dunning-Kruger effect, Historical Antecedents https://en.wikipedia.org/wiki/Dunning–Kruger_effect#Historical_antecedents. <br class="br">1930s, Mortals and Others (1931-35)