It is not human nature we should accuse but the despicable conventions that pervert it.

Aucun homme n'a recu de la nature le droit de commander aux autres. La liberté est un présent du ciel, et chaque individu de la meme espèce a le droit d'en jouir aussitòt qu'il jouit de la raison.

This is a work that cannot be completed except by a society of men of letters and skilled workmen, each working separately on his own part, but all bound together solely by their zeal for the best interests of the human race and a feeling of mutual good will.

We do not know nature; causes hidden in her breast might have produced everything. In your turn, observe the polyp of Trembley: does it not contain in itself the causes which bring about regeneration? Why then would it be absurd to think that there are physical causes by reason of which everything has been made, and to which the whole chain of this vast universe is so necessarily bound and held that, nothing which happens, could have failed to happen,—causes, of which we are so invincibly ignorant that we have had recourse to a God, who, as some aver, is not so much as a logical entity? Thus to destroy chance is not to prove the existence of a supreme being, since there may be some other thing which is neither chance nor God—I mean, nature. It follows that the study of nature can make only unbelievers; and the way of thinking of all its more successful investigators proves this.

To say that man is a compound of strength and weakness, light and darkness, smallness and greatness, is not to indict him, it is to define him.

To prove the Gospels by a miracle is to prove an absurdity by something contrary to nature.

Scepticism is the first step towards truth.

Superstition is more injurious to God than atheism.

We are constantly railing against the passions; we ascribe to them all of man’s afflictions, and we forget that they are also the source of all his pleasures … But what provokes me is that only their adverse side is considered … and yet only passions, and great passions, can raise the soul to great things. Without them there is no sublimity, either in morals or in creativity. Art returns to infancy, and virtue becomes small-minded.

There is no good father who would want to resemble our Heavenly Father

On doit exiger de moi que je cherche la vérité, mais non que je la trouve.

La puissance qui s'acquiert par la violence n'est qu'une usurpation, et ne dure qu'autant que la force de celui qui commande l'emporte sur celle de ceux qui obéissent.

The good of the people must be the great purpose of government. By the laws of nature and of reason, the governors are invested with power to that end. And the greatest good of the people is liberty. It is to the state what health is to the individual.

Genius is present in every age, but the men carrying it within them remain benumbed unless extraordinary events occur to heat up and melt the mass so that it flows forth.

The pit of a theatre is the one place where the tears of virtuous and wicked men alike are mingled.

The following general definition of an animal: a system of different organic molecules that have combined with one another, under the impulsion of a sensation similar to an obtuse and muffled sense of touch given to them by the creator of matter as a whole, until each one of them has found the most suitable position for it shape and comfort.

In order to shake a hypothesis, it is sometimes not necessary to do anything more than push it as far as it will go.

There are three principal means of acquiring knowledge available to us: observation of nature, reflection, and experimentation. Observation collects facts; reflection combines them; experimentation verifies the result of that combination. Our observation of nature must be diligent, our reflection profound, and our experiments exact. We rarely see these three means combined; and for this reason, creative geniuses are not common.

Are we not madder than those first inhabitants of the plain of Sennar? We know that the distance separating the earth from the sky is infinite, and yet we do not stop building our tower.

If exclusive privileges were not granted, and if the financial system would not tend to concentrate wealth, there would be few great fortunes and no quick wealth. When the means of growing rich is divided between a greater number of citizens, wealth will also be more evenly distributed; extreme poverty and extreme wealth would be also rare.

The purpose of an encyclopedia is to collect knowledge disseminated around the globe; to set forth its general system to the men with whom we live, and transmit it to those who will come after us, so that the work of preceding centuries will not become useless to the centuries to come; and so that our offspring, becoming better instructed, will at the same time become more virtuous and happy, and that we should not die without having rendered a service to the human race in the future years to come

Go further, and require each of them to make a contribution: you will see how many things are still missing, and you will be obliged to get the assistance of a large number of men who belong to different classes, priceless men, but to whom the gates of the academies are nonetheless closed because of their social station. All the members of these learned societies are more than is needed for a single object of human science; all the societies together are not sufficient for a science of man in general.

Reason is to the philosopher what grace is to the Christian.Grace causes the Christian to act, reason the philosopher. Other men are carried away by their passions, their actions not being preceded by reflection: these are the men who walk in darkness. On the other hand, the philosopher, even in his passions, acts only after reflection; he walks in the dark, but by a torch. The philosopher forms his principles from an infinity of particular observations. Most people adopt principles without thinking of the observations that have produced them, they believe the maxims exist, so to speak, by themselves. But the philosopher takes maxims from their source; he examines their origin; he knows their proper value, and he makes use of them only in so far as they suit him. Truth is not for the philosopher a mistress who corrupts his imagination and whom he believes to be found everywhere; he contents himself with being able to unravel it where he can perceive it. He does not confound it with probability; he takes for true what is true, for false what is false, for doubtful what is doubtful, and probable what is only probable. He does more, and here you have a great perfection of the philosopher: when he has no reason by which to judge, he knows how to live in suspension of judgment... The philosophical spirit is, then, a spirit of observation and exactness, which relates everything to true principles...

The God of the Christians is a father who makes much of his apples, and very little of his children.

When superstition is allowed to perform the task of old age in dulling the human temperament, we can say goodbye to all excellence in poetry, in painting, and in music.

The more man ascends through the past, and the more he launches into the future, the greater he will be, and all these philosophers and ministers and truth-telling men who have fallen victims to the stupidity of nations, the atrocities of priests, the fury of tyrants, what consolation was left for them in death? This: That prejudice would pass, and that posterity would pour out the vial of ignominy upon their enemies. O Posterity! Holy and sacred stay of the unhappy and the oppressed; thou who art just, thou who art incorruptible, thou who findest the good man, who unmaskest the hypocrite, who breakest down the tyrant, may thy sure faith, thy consoling faith never, never abandon me!

Et ses mains ourdiraient les entrailles du prêtre, Au défaut d’un cordon pour étrangler les rois.

Justice is the first virtue of those who command, and stops the complaints of those who obey.

I have often seen an actor laugh off the stage, but I don’t remember ever having seen one weep.

How old the world is! I walk between two eternities... What is my fleeting existence in comparison with that decaying rock, that valley digging its channel ever deeper, that forest that is tottering and those great masses above my head about to fall? I see the marble of tombs crumbling into dust; and yet I don’t want to die!

The wisest among us is very lucky never to have met the woman, be she beautiful or ugly, intelligent or stupid, who could drive him crazy enough to be fit to be put into an asylum.

As for our celebrated lawgivers, who have cast us in our present awkward mold, you may be sure that they have acted to serve their interests and not ours. Witness all our political, civil, and religious institutions — examine them thoroughly: unless I am very much mistaken, you will see how, through the ages, the human race has been broken to the halter that a handful of rascals were itching to impose. Watch out for the fellow who talks about putting things in order! Putting things in order always means getting other people under your control.

Man was born to live with his fellow human beings. Separate him, isolate him, his character will go bad, a thousand ridiculous affects will invade his heart, extravagant thoughts will germinate in his brain, like thorns in an uncultivated land.

It has been said that love robs those who have it of their wit, and gives it to those who have none.

L'esprit de l'escalier

Pithy sentences are like sharp nails which force truth upon our memory.

The best doctor is the one you run for and can't find.

[Jews are] angry and brutish people, vile and vulgar men, slaves worthy of the yoke [Talmudism] which you bear... Go, take back your books and remove yourselves from me. [ The Talmud ] taught the Jews to steal the goods of Christians, to regard them as savage beasts, to push them over the precipice... to kill them with impunity and to utter every morning the most horrible imprecations against them.

Happiest are the people who give most happiness to others.

There are things I can't force. I must adjust. There are times when the greatest change needed is a change of my viewpoint.

I believe in God, although I live very happily with atheists... It is very important not to mistake hemlock for parsley; but not at all so to believe or not in God.

I am beginning to feel that I am growing old; soon, I shall have to eat mush like children. I shall no longer be able to speak, which will be a rather great advantage for others and but a small inconvenience for myself.... The time in which I count in years is gone; that in which I count in days is here.... I had thought that the fibers of the heart would grow callous with age, it's not at all the case. I am not sure that my sensitivity hasn't increased; everything moves me, affects me.... To fade out between a man feeling your pulse and another bothering your head; not to know where one comes from, why one came, where one is going ...

There is no moral precept that does not have something inconvenient about it.

Evil always turns up in this world through some genius or other.

We are far more liable to catch the vices than the virtues of our associates.

Distance is a great promoter of admiration!

[Africans are] always vicious... mostly inclined to lasciviousness, vengeance, theft and lies.

The arbitrary rule of a just and enlightened prince is always bad. His virtues are the most dangerous and the surest form of seduction: they lull a people imperceptibly into the habit of loving, respecting, and serving his successor, whoever that successor may be, no matter how wicked or stupid.

[http://www.traduire.de/Diderot/G%2BD_1.htm Le Neveu de Rameau - Diderot et Goethe]

There is only one passion, the passion for happiness.