“The investigation of the meaning of words is the beginning of education”

“The hours of folly are measured by the clock, but of wisdom no clock can measure.”

“Not to unlearn what you have learned is the most necessary kind of learning.”

“It is well for people who think to change their minds occasionally in order to keep them clean. For those who do not think, it is best to at least rearrange their prejudices once in a while”

“One must be a wise reader to quote wisely and well”

“Who knows, the mind has the key to all things besides”