There is no result in nature without a cause; understand the cause and you will have no need of the experiment.

Here is a thing which the more it is needed the more it is rejected: and this is advice, which is unwillingly heeded by those who most need it, that is to say, by the ignorant.

Tell me if anything was ever done.

Painting is poetry that is seen rather than felt, and poetry is painting that is felt rather than seen.

There is no doubt that truth is to falsehood as light is to darkness; and so excellent a thing is truth that even when it touches humble and lowly matters, it still incomparably exceeds the uncertainty and falsehood in which great and elevated discourses are clothed; because even if falsehood be the fifth element of our minds, notwithstanding this, truth is the supreme nourishment of the higher intellects.

Science is the observation of things possible, whether present or past.

A bird is an instrument working according to mathematical law, which instrument it is within the capacity of man to reproduce with all its movements.

Do not reveal, if liberty is precious to you; my face is the prison of love.

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

Although human ingenuity may devise various inventions which, by the help of various instruments, answer to one and the same purpose, yet will it never discover any inventions more beautiful, more simple or more practical than those of nature.

One shall be born from small beginnings which will rapidly become vast. This will respect no created thing, rather will it, by its power, transform almost every thing from its own nature into another.

Faults are more easily recognized in the works of others than in our own.

We are deceived by promises and time disappoints us...

Nature never breaks her laws.

Where there is most feeling, there is the greatest martyrdom.

One can have no smaller or greater mastery than mastery of oneself.

It is ill to praise, and worse to blame, the thing which you do not understand.

We should not desire the impossible.

Not to punish evil is equivalent to authorizing it.

Experience is a truer guide than the words of others.

Darkness is absence of light.
Shadow is diminution of light.

The grave will fall in upon him who digs it.

Virtue is our true wealth and the true reward of its possessor; it cannot be lost, it never deserts us until life leaves us.

The painter's work will be of little merit if he takes the painting of others as his standard, but if he studies from nature he will produce good fruits.

Study without desire spoils the memory, and it retains nothing that it takes in.

There is no human experience that can be termed true science unless it can be mathematically demonstrated. And if thou sayest that the sciences which begin and end in the mind are true, this cannot be conceded, but must be denied for many reasons, and firstly because in such mental discourses experience is eliminated, and without experience there can be no certainty.

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

Truth is so excellent, that if it praises but small things they become noble.

Shadow is not the absence of light, merely the obstruction of the luminous rays by an opaque body.

A painter should begin every canvas with a wash of black, because all things in nature are dark except where exposed by the light.