The important thing is not to stop questioning. Curiosity has its own reason for existing. One cannot help but be in awe¹ when he contemplates² the mysteries of eternity³, of life, of the marvelous structure of reality. It is enough if one tries merely to comprehend a little of this mystery every day. Never lose a holy curiosity.

Albert Einstein (1879 - 1955)

You can question somebody's views and their judgment⁴ without questioning their motives⁵ or patriotism⁶.

Barack Obama (1961 - ), University of Michigan Commencement, 2010

In all affairs it's a healthy thing now and then to hang a question mark on the things you have long taken for granted.

Bertrand Russell (1872 - 1970)

Look at all the sentences which seem true and question them.

David Reisman

A thinker sees his own actions as experiments and questions--as attempts to find out something. Success and failure are for him answers above all.

Friedrich Nietzsche (1844 - 1900), The Gay Science, section 41

One's first step in wisdom is to question everything - and one's last is to come to terms with everything.

Georg Christoph Lichtenberg (1742 - 1799)

A young man is embarrassed to question an older one.

Homer (800 BC - 700 BC), The Odyssey⁷

It is better to know some of the questions than all of the answers.

James Thurber (1894 - 1961)

If you ask too many questions, you will find no answers, only more questions.

Monica Fairview, Darcy Cousins, 2010

Ask questions from your heart and you will be answered from the heart.

Omaha Proverb

There are two sides to every question.

Protagoras (485 BC - 421 BC), from Diogenes Laertius, Lives of Eminent⁸ Philosophers

It is not every question that deserves an answer.

Publilius Syrus (~100 BC), Maxims⁹

A wise man's question contains half the answer.

Solomon Ibn Gabirol

The most erroneous stories are those we think we know best - and therefore never scrutinize¹⁰ or question.

Stephen Jay Gould (1941 - 2002)

So many men so many questions.

(Quot Homines Tot Sententiae)

Terence (185 BC - 159 BC)

The outcome of any serious research can only be to make two questions grow where only one grew before.

Thorstein Veblen (1857 - 1929)

Judge of a man by his questions rather than by his answers.

Voltaire (1694 - 1778)