Denis Diderot

"Scepticism is the first step towards truth."

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

"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."

"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."

"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."

"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."

"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."

"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..."

"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."

"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"

"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."

"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."

"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."

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

"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."

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

"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."

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

"Poetry must have something in it that is barbaric, vast and wild."

"When shall we see poets born? After a time of disasters and great misfortunes, when harrowed nations begin to breathe again. And then, shaken by the terror of such spectacles, imaginations will paint things entirely strange to those who have not witnessed them."

"Shakespeare’s fault is not the greatest into which a poet may fall. It merely indicates a deficiency of taste."

"Every man has his dignity. I'm willing to forget mine, but at my own discretion and not when someone else tells me to."

"If there is one realm in which it is essential to be sublime, it is in wickedness. You spit on a petty thief, but you can’t deny a kind of respect for the great criminal."

"Bad company is as instructive as licentiousness. One makes up for the loss of one’s innocence with the loss of one’s prejudices."

"People praise virtue, but they hate it, they run away from it. It freezes you to death, and in this world you've got to keep your feet warm."

"Je m’entretiens avec moi-même de politique, d’amour, de goût ou de philosophie ; j’abandonne mon esprit à tout son libertinage ; je le laisse maître de suivre la première idée sage ou folle qui se présente … Mes pensées ce sont mes catins."

"La reconnaissance est un fardeau, et tout fardeau est fait pour être secoué."

"We swallow greedily any lie that flatters us, but we sip only little by little at a truth we find bitter."

"If your little savage were left to himself and be allowed to retain all his ignorance, he would in time join the infant’s reasoning to the grown man’s passion, he would strangle his father and sleep with his mother."

"What a hell of an economic system! Some are replete with everything while others, whose stomachs are no less demanding, whose hunger is just as recurrent, have nothing to bite on. The worst of it is the constrained posture need puts you in. The needy man does not walk like the rest; he skips, slithers, twists, crawls."

"All abstract sciences are nothing but the study of relations between signs."

"We are all instruments endowed with feeling and memory. Our senses are so many strings that are struck by surrounding objects and that also frequently strike themselves."

"Do you see this egg? With this you can topple every theological theory, every church or temple in the world. What is it, this egg, before the seed is introduced into it? An insentient mass. And after the seed has been introduced to into it? What is it then? An insentient mass. For what is the seed itself other than a crude and inanimate fluid? How is this mass to make a transition to a different structure, to sentience, to life? Through heat. And what will produce that heat in it? Motion."

"Égaré dans une forêt immense pendant la nuit, je n’ai qu’une petite lumière pour me conduire. Survient un inconnu qui me dit : Mon ami, souffle ta bougie pour mieux trouver ton chemin. Cet inconnu est un théologien. — No VIII"

"Disturbances in society are never more fearful than when those who are stirring up the trouble can use the pretext of religion to mask their true designs."

"[L]e philosophe n'a jamais tué de prêtres et le prêtre a tué beaucoup de philosophes..."

"In any country where talent and virtue produce no advancement, money will be the national god. Its inhabitants will either have to possess money or make others believe that they do. Wealth will be the highest virtue, poverty the greatest vice. Those who have money will display it in every imaginable way. If their ostentation does not exceed their fortune, all will be well. But if their ostentation does exceed their fortune they will ruin themselves. In such a country, the greatest fortunes will vanish in the twinkling of an eye. Those who don't have money will ruin themselves with vain efforts to conceal their poverty. That is one kind of affluence: the outward sign of wealth for a small number, the mask of poverty for the majority, and a source of corruption for all."

"Morals are in all countries the result of legislation and government; they are not African or Asian or European: they are good or bad."

"Patriotism is an ephemeral motive that scarcely ever outlasts the particular threat to society that aroused it."

"The possibility of divorce renders both marriage partners stricter in their observance of the duties they owe to each other. Divorces help to improve morals and to increase the population."

"The general interest of the masses might take the place of the insight of genius if it were allowed freedom of action."

"The decisions of law courts should never be printed: in the long run, they form a counterauthority to the law."

"The blood of Jesus Christ can cover a multitude of sins, it seems to me."

"The most dangerous madmen are those created by religion, and … people whose aim is to disrupt society always know how to make good use of them on occasion."

"There is not a Musselman alive who would not imagine that he was performing an action pleasing to God and his Holy Prophet by exterminating every Christian on earth, while the Christians are scarcely more tolerant on their side."

"Jacques said that his master said that everything good or evil we encounter here below was written on high."

"How did they meet? By chance, like everybody … Where did they come from? From the nearest place. Where were they going? Do we know where we are going?"

"How easy it is to tell tales!"

"The first promise exchanged by two beings of flesh was at the foot of a rock that was crumbling into dust; they took as witness for their constancy a sky that is not the same for a single instant; everything changed in them and around them, and they believed their hearts free of vicissitudes. O children! always children!"