All sciences are vain and full of errors that are not born of Experience, the mother of all Knowledge.

“I have always felt it is my destiny to build a machine that would allow man to fly.

The deeper the feeling, the greater the pain

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

The time will come when men such as I will look upon the murder of animals as they now look on the murder of men.

Time stays long enough for those who use it.

Intellectual passion drives out sensuality.

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

Water is the driving force in nature.

God sells us all things at the price of labor.

He who thinks little errs much…

A poet knows he has achieved perfection not when there is nothing left to add, but when there is nothing left to take away.

Our life is made by the death of others.

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

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

My body will not be a tomb for other creatures.

Learn how to see. Realize that everything connects to everything else.

He who possesses most must be most afraid of loss.

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.