Leonardo's Notebooks

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

I awoke only to find that the rest of the world was still asleep.

Man has much power of discourse which for the most part is vain and false; animals have but little, but it is useful and true, and a small truth is better than a great lie.

The water you touch in a river is the last of that which has passed, and the first of that which is coming. Thus it is with time present. Life, if well spent, is long.

Men fight wars and destroy everything around them. The earth should open and swallow them up. He who does not value life does not deserve it. Never destroy another life through rage, or through malice.

The men of experiment are like the ant; they only collect and use. But the bee gathers its materials from the flowers of the garden and of the field, but transforms and digests it by a power of its own.

If the painter wishes to see beauties that charm him, it lies in his power to create them, and if he wishes to see monstrosities that are frightful, ridiculous, or truly pitiable, he is lord and God thereof.

Like a kingdom divided, which rushes to its doom, the mind that engages in subjects of too great variety becomes confused and weakened.

Those who fall in love with practice without science are like a sailor who enters a ship without a helm or a compass, and who never can be certain whither he is going.

It is as great an error to speak well of a worthless man as to speak ill of a good man.

For nothing can be loved or hated unless it is first known.

I am fully conscious that, not being a literary man , certain presumptuous persons will think that they may reasonably blame me; alleging that I am not a man of letters. Foolish folks! do they not know that I might retort as Marius did to the Roman Patricians by saying: That they, who deck themselves out in the labours of others will not allow me my own. They will say that I, having no literary skill, cannot properly express that which I desire to treat of, but they do not know that my subjects are to be dealt with by experience rather than by words; and experience has been the mistress of those who wrote well. And so, as mistress, I will cite her in all cases.

No counsel is more trustworthy than that which is given upon ships that are in peril.

When the fig-tree stood without fruit no one looked at it. Wishing by producing this fruit be praised by men, it was bent and broken by them.

Creatures shall be seen on the earth who will always be fighting one another, with the greatest losses and frequent deaths on either side. There will be no bounds to their malice; by their strong limbs the vast forests of the world shall be laid low; and when they are filled with food they shall gratify their desires by dealing out death, affliction, labour, terror, and banishment to every living thing; and then from their boundless pride they will desire to rise towards heaven, but the excessive weight of their limbs will hold them down. Nothing shall remain on the earth or under the earth or in the waters that shall not be pursued, disturbed, or spoiled, and that which is in one country removed into another. And their bodies shall be made the tomb and the means of transit of all the living bodies they have slain. O earth, why do you not open and hurl them into the deep fissures of thy vast abysses and caverns, and no longer display in the sight of heaven so cruel and horrible a monster?