“A great many people mistake opinions for thought.”
“A mistake made by many people with great convictions is that they will let nothing stand in the way of their views, not even kindness.”
“There are a great many opinions in this world, and a good half of them are professed by people who have never been in trouble."(The Mill)”
“Many great ideas have happened by mistake.”
“No man ever became great or good except through many and great mistakes.”
“I never make the mistake of arguing with people for whose opinions I have no respect.”