“A man's life is what his thoughts make of it.”
“What was once thought can never be unthought.”
“Those that think must govern those that toil.”
“Man's greatness lies in his power of thought.”
“Every thought we think is creating our future.”
“All thought is naught but a footnote to Plato.”
“Man is the only creature who has a nasty mind.”
“If I look confused it is because I am thinking.”
“I was a freethinker before I knew how to think.”
“Arouse the mind without resting it on anything.”
“Thinking is the talking of the soul with itself.”
“We think in generalities, but we live in detail.”
“Think twice before you speak to a friend in need.”
“What is the hardest thing in the world? To think.”
“Thought takes man out of servitude, into freedom.”
“I am not what I think. I am thinking what I think.”
“How can I know what I think till I see what I say?”
“It's only a thought, and a thought can be changed.”
“Where all men think alike, no one thinks very much.”
“What's going on in the inside shows on the outside.”
“Clarity is the counterbalance of profound thoughts.”
“Nothing pains some people more than having to think.”
“Thinking is not to agree or disagree. That is voting.”
“Great thoughts reduced to practice become great acts.”
“Sooner or later, false thinking brings wrong conduct.”
“No man can think clearly when his fists are clenched.”
“Life consists in what a person is thinking of all day.”
“Thinking is one thing no one has ever been able to tax.”
“There is nothing good or bad, but thinking makes it so.”
“A man is infinitely more complicated than his thoughts.”