Thinking is the hardest work there is, which is probably the reason why so few engage in it.
Henry Ford
Failure is simply the opportunity to begin again, this time more intelligently.
There are only two races on this planet - the intelligent and the stupid.
John Fowles
The voice of the intellect is a soft one, but it does not rest until it has gained a hearing.
Sigmund Freud
What a distressing contrast there is between the radiant intelligence of the child and the feeble mentality of the average adult.
Man knows so much and does so little.
R. Buckminster Fuller
We all agree that pessimism is a mark of superior intellect.
John Kenneth Galbraith
It is not worth an intelligent man's time to be in the majority. By definition, there are already enough people to do that.
G. H. Hardy
The intellect of the wise is like glass; it admits the light of heaven and reflects it.
Augustus Hare
Be what you are. This is the first step toward becoming better than you are.
Julius Charles Hare