Iron rusts from disuse; water loses its purity from stagnation... even so does inaction sap the vigor of the mind.

Where the spirit does not work with the hand, there is no art.

Anyone who conducts an argument by appealing to authority is not using his intelligence; he is just using his memory.

For once you have tasted flight you will walk the earth with your eyes turned skywards, for there you have been and there you will long to return.

The poet ranks far below the painter in the representation of visible things, and far below the musician in that of invisible things.

Nature never breaks her own laws.

Where there is shouting, there is no true knowledge.

As every divided kingdom falls, so every mind divided between many studies confounds and saps itself.

Experience does not err. Only your judgments err by expecting from her what is not in her power.

He who wishes to be rich in a day will be hanged in a year.

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

A well-spent day brings happy sleep.

Learning never exhausts the mind.

Life well spent is long.

Nothing strengthens authority so much as silence.

Although nature commences with reason and ends in experience it is necessary for us to do the opposite, that is to commence with experience and from this to proceed to investigate the reason.

It had long since come to my attention that people of accomplishment rarely sat back and let things happen to them. They went out and happened to things.

Human subtlety will never devise an invention more beautiful, more simple or more direct than does nature because in her inventions nothing is lacking, and nothing is superfluous.

He who loves practice without theory is like the sailor who boards ship without a rudder and compass and never knows where he may cast.

Art is never finished, only abandoned.

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 human foot is a masterpiece of engineering and a work of art.

Beyond a doubt truth bears the same relation to falsehood as light to darkness.

I have been impressed with the urgency of doing. Knowing is not enough; we must apply. Being willing is not enough; we must do.

Life is pretty simple: You do some stuff. Most fails. Some works. You do more of what works. If it works big, others quickly copy it. Then you do something else. The trick is the doing something else.

Common Sense is that which judges the things given to it by other senses.

The truth of things is the chief nutriment of superior intellects.

All our knowledge has its origins in our perceptions.

You can have no dominion greater or less than that over yourself.

The greatest deception men suffer is from their own opinions.

You do ill if you praise, but worse if you censure, what you do not understand.

It's easier to resist at the beginning than at the end.

As a well-spent day brings happy sleep, so a life well spent brings happy death.

Why does the eye see a thing more clearly in dreams than the imagination when awake?

Just as courage imperils life, fear protects it.

In rivers, the water that you touch is the last of what has passed and the first of that which comes; so with present time.

There are three classes of people: those who see, those who see when they are shown, those who do not see.

Blinding ignorance does mislead us. O! Wretched mortals, open your eyes!

Simplicity is the ultimate sophistication.

I have wasted my hours.

While I thought that I was learning how to live, I have been learning how to die.

Iron rusts from disuse; water loses its purity from stagnation... even so does inaction sap the vigor of the mind.

Our life is made by the death of others.

The smallest feline is a masterpiece.

He who is fixed to a star does not change his mind.

Marriage is like putting your hand into a bag of snakes in the hope of pulling out an eel.

Who sows virtue reaps honor.

I have offended God and mankind because my work didn't reach the quality it should have.

The noblest pleasure is the joy of understanding.