intelligence

"The difference between stupidity and genius is that genius has its limits."

"It's not that I'm so smart, it's just that I stay with problems longer."

"Any man who reads too much and uses his own brain too little falls into lazy habits of thinking."

"Intellectuals solve problems, geniuses prevent them."

"We should take care not to make the intellect our god it has, of course, powerful muscles, but no personality."

"Failure is simply the opportunity to begin again, this time more intelligently."