Leonardo da Vinci

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

Our life is made by the death of others.

Medicine is the restoration of discordant elements; sickness is the discord of the elements infused into the living body.

The painter who draws merely by practice and by eye, without any reason, is like a mirror which copies every thing placed in front of it without being conscious of their existence.

Nothing strengthens authority so much as silence.

Just as courage is the danger of life, so is fear its safeguard.

Just as courage imperils life, fear protects it.

Every action needs to be prompted by a motive.

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.

Good men by nature, wish to know. I know that many will call this useless work... men who desire nothing but material riches and are absolutely devoid of that of wisdom, which is the food and only true riches of the mind.

Nature is the source of all true knowledge. She has her own logic, her own laws, she has no effect without cause nor invention without necessity.

There are four Powers: memory and intellect, desire and covetousness. The two first are mental and the others sensual. The three senses: sight, hearing and smell cannot well be prevented; touch and taste not at all.