What can I know? What ought I to do? What can I hope?
Immanuel Kant

All the interests of my reason, speculative as well as practical, combine in the three following questions: 1. What can I know? 2. What ought I to do? 3. What may I hope?
Immanuel Kant

A major source of objection to a free economy is precisely that group thinks they ought to want. Underlying most arguments against the free market is a lack of belief in freedom itself.
Milton Friedman

It will, I believe, be everywhere found, that as the clergy are, or are not what they ought to be, so are the rest of the nation.
Jane Austen

General benevolence, but not general friendship, made a man what he ought to be.
Jane Austen

There are so many things about which some old man ought to tell one while one is little; for when one is grown one would know them as a matter of course.
Rainer Maria Rilke

I'm proof against that word failure. I've seen behind it. The only failure a man ought to fear is failure of cleaving to the purpose he sees to be best.
George Eliot

An author ought to write for the youth of his own generation, the critics of the next, and the schoolmaster of ever afterwards.
F. Scott Fitzgerald

A scientific man ought to have no wishes, no affections, - a mere heart of stone.
Charles Darwin

The highest possible stage in moral culture is when we recognize that we ought to control our thoughts.
Charles Darwin

Neutrality is a negative word. It does not express what America ought to feel. We are not trying to keep out of trouble; we are trying to preserve the foundations on which peace may be rebuilt.
Woodrow Wilson

I think remorse ought to stop biting the consciences that feed it.
Ogden Nash

All men having power ought to be distrusted to a certain degree.
James Madison

Learned Institutions ought to be favorite objects with every free people. They throw that light over the public mind which is the best security against crafty and dangerous encroachments on the public liberty.
James Madison

The truth is that all men having power ought to be mistrusted.
James Madison

If we are to take for the criterion of truth the majority of suffrages, they ought to be gotten from those philosophic and patriotic citizens who cultivate their reason.
James Madison

The bad poet is usually unconscious where he ought to be conscious, and conscious where he ought to be unconscious.
T. S. Eliot

The want of belief is a defect that ought to be concealed when it cannot be overcome.
Jonathan Swift

I have often met with happiness after some imprudent step which ought to have brought ruin upon me, and although passing a vote of censure upon myself I would thank God for his mercy.
Giacomo Casanova

Instead of this absurd division into sexes they ought to class people as static and dynamic.
Evelyn Waugh