This article is taken from Voltaire's Philosophical Dictionary, first published in 1764. It shows that, even after the publication of Candide, the philosophe continued to think about and to criticize the notion of optimism.

As in Candide, Voltaire here uses humor to great effect, but he addresses the arguments of his adversaries more directly. For this reason, the article may be useful for clarifying certain aspects of the conte.

This translation is taken from Voltaire, Philosophical Dictionary, edited and translated by Theodore Besterman (London and New York: Penguin Books, 1972), p. 68-74.

There was a fine row in the schools, and even among people who think, when Leibniz, paraphrasing Plato, built his edifice of the best of possible worlds, and imagined that all was for the best. He affirmed in the north of Germany that god could make only a single world. Plato had at least left him free to make five, because there are only five regular solids: the tetrahedron or three-faced pyramid with uniform base, the cube, the hexahedron, the dodecahedron, the icosahedron. But our world is not shaped like any of Plato's five bodies, he had allowed god a sixth manner.

That will do for Plato. Leibniz, who was certainly a better geometer than he, and a more profound metaphysician, did mankind the service of explaining that we ought to be entirely satisfied, and that god could do no more for us, that he had necessarily chosen, among all the possibilities, what was undeniably the best one.

"What will become of original sin?" they shouted at him. "It will become what it can," said Leibniz and his friends; but in public he wrote that original sin was necessarily part of the best of worlds.

What! to be chased from a place of delights, where we would have lived for ever if an apple had not been eaten! What! produce in wretchedness wretched children who will suffer everything, who will make others suffer everything! What! to undergo every illness, feel every sorrow, die in pain, and for refreshment be burned in the eternity of centuries! Is this really the best lot that was available? This is not too good for us; and how can it be good for good?

Leibniz realized that these questions were unanswerable: so he wrote thick books in which he did not agree with himself.

A Lucullus in good health, dining well with his friends and his mistress in the house of Apollo, can say laughingly that there is no devil; but let him put his head out of the window and he will see unhappy people; let him suffer a fever and he will be unhappy himself.

I do not like to quote; it is usually a ticklish job: what precedes and follows the passage quoted is passed over, and one exposes oneself to a thousand quarrels. Still, I must quote Lactantius, church father, who, in his chapter XIII, of his On the Wrath of God puts these words into the mouth of Epicurus:

Either god wants to remove the evil from this world, and cannot, or he can, and does not want to; or he neither wants to nor can; or he wants to and can. If he wants to but cannot, this is impotence, which is contrary to the nature of god; if he can but does not want to, this is wickedness, which is no less contrary to his nature; if he neither can nor wants to this is at once wickedness and impotence; if he wants to and can (which is the only one of these possibilities fitting for god) whence then comes the evil which is on earth?

The argument is powerful; so that Lactantius answers it very badly, saying that god wants evil but that he has given us the wisdom with which one acquires the good. It must be admitted that this answer is quite weak in comparison with the objection, for it assumes that god could create wisdom only by producing evil; besides our wisdom is pretty ridiculous!

Bolingbroke, Shaftesbury and Pope, who embodied their ideas, do not resolve the question any better than the others: their All is good means nothing more than that all is controlled by immutable laws. Who does not know that? You tell us nothing new when you observe, as all little children have done, that flies are born to be eaten by spiders, spiders by swallows, swallows by shrikes, shrikes by eagles, eagles to be killed by men, men to kill one another, and to be eaten by worms, and then, all but one in a thousand, by devils.

Here we have a clear and fixed order among every kind of animal. There is order everywhere. When a stone is formed in my bladder it is by means of admirable mechanics: calculous juices pass little by little into my blood, they filter into the kidneys, pass through the ureters, deposit themselves in my bladder, and assemble there by an excellent Newtonian attraction; the stone is formed, gets bigger, I suffer pains a thousand times worse than death, by the most elegant arrangement in the world. A surgeon, having perfected the art invented by Tubalcain, comes to thrust a sharp and cutting iron into the perineum, and takes hold of my stone with his pincers. It breaks under his efforts by a necessary mechanism; and by the same mechanism I die in frightful torments. All this is good, all this is the evident consequence of inalterable physical principles. I agree with them, and I knew it as well as you did.

If we were without feeling there would be no reason to object to this cause and effect. But this is not the point. We are inquiring whether there are any perceptible evils, and whence they come. "There are no evils," says Pope in his fourth essay on the All is good; "or if there are particular evils, they form the common good."

A strange general good! composed of the stone, the gout, all crimes, all suffering, death and damnation.

The fall of man is the platter we stick on all there particular diseases of the body and the soul, which are called "general health". But Shaftesbury and Bolingbroke derided original sin; Pope does not refer to it; it is obvious that their system undermines the Christian religion at its foundations, and explains nothing at all.

Nevertheless this system has recently been approved by several theologians who readily accept contradictions. Capital! we must not begrudge anybody the consolation of reasoning as best he can about the deluge of evils by which we are inundated. It is right to allow the incurable to eat what they like. It has even been claimed that this system is consoling. "God," says Pope, "sees perish with equal eye the hero and the sparrow, an atom or a thousand planets precipitated into ruin, the formation of a soap-bubble or a world."

Here, I must admit, we have a pleasant consolation. Do you not find a great palliative in the prescription of lord Shaftesbury, who says that god is not going to upset his eternal laws for so puny an animal as man? It must at least be admitted that this puny animal has the right to cry out humbly, and to seek to understand, in crying, why these eternal laws are not made for the well-being of every individual.

This system of All is good represents the author of nature only as a powerful and maleficent king, who does not care, so long as he carries out his plan, that it costs four or five hundred thousand men their lives, and that the others drag out their days in want and in tears.

So far from the notion of the best of possible worlds being consoling, it drives to despair the philosophers who embrace it. The problem of good and evil remains an inexplicable chaos for those who seek in good faith. It is an intellectual exercise for those who argue: they are convicts who play with their chains. As for the unthinking mass, it rather resembles fish who have been moved from a river to a reservoir. They do not suspect that they are there to be eaten in lent: nor do we know anything by our own resources about the causes of our destiny.

Let us put at the end of nearly all chapters on metaphysics the two letters used by Roman judges when they could not understand a lawsuit: N. L., non liquet, this is not clear.