“Without contraries is no progression.”

“A true teacher defends his students against his own personal influences”

“My wife was too beautiful for words, but not for arguments.”

“The man who never alters his opinions is like standing water, and breeds reptiles of the mind”

“Where so many hours have been spent in convincing myself that I am right, is there not some reason to fear I may be wrong?”

“Neutrality is at times a graver sin than belligerence”