Change is the law of life, and those who look only to the past or the present are certain to miss the future.

We live in a moment of history where change is so speeded up that we begin to see the present only when it is already disappearing.

To be perfect is to have changed often.

The absurd man is he who never changes.

The trouble with our times is that the future is not what it used to be.

Progress is impossible without change, and those who cannot change their minds cannot change anything.

The art of progress is to preserve order amid change and to preserve change amid order.

The world acquires value only through its extremes and endures only through moderation; extremists make the world great, the moderates give it stability.

The greatest mistake you can make in life is to be continually fearing you will make one.

The absence of alternatives clears the mind marvelously.

I hold that that man is in the right who is most closely in league with the future.

The perpetual obstacle to human advancement is custom.

Two dangers constantly threaten the world: order and disorder.

Human history becomes more and more a race between education and catastrophe.

When you're through changing, you're through.

Speak comfortable words!

The ill and unfit choice of words wonderfully obstructs the understanding.

Oh, rather give me commentators plain, Who with no deep researches vex the brain.

He that knows least commonly presumes most.

A memorandum is written not to inform the reader, but to protect the writer.

I think the whole glory of writing lies in the fact that it forces us out of ourselves into the lives of others.

Tact is the ability to describe others as they see themselves.

A sharp tongue is the only edged tool that grows keener with constant use.

Some people can stay longer in an hour than others can in a week.

It is much easier to be critical than to be correct.

If a man is often the subject of conversation he soon becomes the subject of criticism.

I begin to suspect man's bewilderment is the measure of his wisdom.

A word of encouragement during a failure is worth more than a whole book of praise after a success.

To them I said, "The truth would be literally nothing but the shadows of the images."

Between the idea and the reality, Between the motion and the act, Falls the shadow.

What we do not understand, we do not possess.

We prove what we want to prove, and the real difficulty is to know what we want to prove.

Imagination is more important than knowledge.

Simplicity is the ultimate sophistication.

All the effects of nature are only the mathematical consequence of a small number of immutable laws.

We live in a Newtonian world of Einsteinian physics ruled by Frankensteinian logic.

He that will not reason is a bigot, He that cannot reason is a fool, He that dares not reason is a slave.

Reason often makes mistakes, but conscience never does.

I am dying with the help of too many physicians.

The greatest difficulty of the intellectual is distinguishing the important from the unimportant.

Mediocrity knows nothing higher than itself, but talent instantly recognizes genius.

One's mind, once stretched by a new idea, never regains its original dimensions.

Everybody is ignorant, only on different subjects.

What we need, gentlemen, is a completely brand new idea that has been thoroughly tested.

If a man will begin with certainties, he shall end in doubts; but if he will be content to begin with doubts, he shall end in certainties.

Any new theory first is attacked as absurd; then it is admitted to be true, but obvious and insignificant; finally it seems to be important, so important that its adversaries claim that they themselves discovered it!

Man errs so long as he strives.

The secret of good direction does not consist of solving problems, but in identifying them.

Every good laboratory consists of first rate men working in great harmony to insure the progress of science; but down at the end of the hall is an unsociable, wrong-headed fellow working on unprofitable lines, and in his hands lies the hope of discovery.

Creativity is so delicate a flower that praise tends to make it bloom, while discouragement often nips it in the bud. Any of us will put out more ideas if our efforts are appreciated.

The universe is full of magical things patiently waiting for our wits to grow sharper.

A hen is only an egg's way of making another egg.

Research is to see what everybody else has seen, and to think what nobody else has thought.

Everything should be made as simple as possible, but not simpler.

Genius is one percent inspiration and ninety-nine percent perspiration.

Experts ranked in serried rows, Filled the enormous plaza full, But only one is there who knows, And he's the man who fights the bull. [In more ways than one. -ed.]

The very first step toward success in any occupation is to become interested in it.

Nothing ever succeeds which exuberant spirits have not helped to produce.

It is always pleasant to be urged to do something on the grounds that one can do it well.

That man is truly free who desires what he is able to perform, and does what he desires.

We are continually faced with a series of great opportunities brilliantly disguised as insoluble problems.

Adversity is the state in which a man most easily becomes acquainted with himself, being especially free from admirers then.

Doing is the great thing. For if, resolutely, people do what is right, in time they come to like doing it.

Method facilitates every kind of business, and by making it easy, makes it agreeable and also successful.

From compromise and things half-done, Keep me, with stern and stubborn pride, And when at last the fight is won, God, keep me still unsatisfied.

Success is partial to the persistent person.

Men of lofty genius when they are doing the least work are most active.

There is a tide in the affairs of men, Which, taken at the flood, leads on to fortune; Omitted, all the voyages of their life, Is bound in shallows and miseries.

This, above all: Unto thine own self be true, And it must follow, as the night the day, Thous canst not then be false to any man.

Truth emerges more readily from error than confusion.

Life must be lived forwards, But can only be understood backwards.

Half the failures of life arise from pulling in one's horse as it is leaping.

I shall be telling this with a sign, Somewhere ages and ages hence: Two roads diverged in a wood, And I took the one less traveled by, And that has made all the difference.

This could be such a beautiful world if we could all care just a little more.

We travel together, passengers on a little space ship, dependent on its vulnerable supplies of air and soil, preserved from annihilation only by the care, the work, and I will say the love, we give our fragile craft.

Fear less, hope more; Eat less, chew more; Whine less, breathe more; Talk less, say more; Hate less, love more; And all good things are yours.

The purpose of life is the expansion of happiness.

I love those who can smile in trouble, who can gather strength from distress, and grow brave by reflection. 'Tis the business of little minds to shrink, but they whose heart is firm, and whose conscience approves their conduct, will pursue their principles unto death.

The world is a comedy to those that think, a tragedy to those that feel.

He who has a why to live can bear almost any how.

For all sad words of tongue or pen, The saddest are these, "It might have been."