Treatise on Tolerance on the occasion of the death of Jean Calas (1763) (Voltaire)

Voltaire wrote this book after the trial of Jean Calas, a Protestant wrongly accused of murdering her son converted to Catholicism, March 9, 1762, in Toulouse. So this is a work written « reaction » that Voltaire saw as an injustice of his countrymen, who was due to religious intolerance.

This incident was the starting point of his plea for tolerance :

Treatise on Tolerance on the occasion of the death of Jean Calas (1763) of Voltaire

Such was the state of this amazing adventure, when she gave birth to impartial, but sensitive, the aim of presenting to the public some thoughts on tolerance, on indulgence on the pity that Father Houtteville called dogma monstrous in its turgid declamation and wrong on the facts, and that reason called the preserve of nature .

T reaty on Tolerance on the occasion of the death of Jean Calas (1763) Voltaire

View original image
The cruel death of Jean Calas – Voltaire

Voltaire attacks the religious. And it is especially Catholics, have mastered the art of intolerance. In introduction, it should be recalled that Voltaire is not atheist (one who denies the existence of God). He is Deist : he has the intuition of a higher entity, inaccessible by reason. He does not believe in the Christian God. He believes in something beyond us, dizzying (like Pascal before him).

The world embarrasses me, and I can not think, That this clock exists and has no watchmaker. Voltaire, Poems

The analysis of the facts leads to two assumptions that Voltaire however lead to the same conclusion:

  1. The judges of Toulouse, led into fanaticism by the people, have broken on the wheel an innocent family man;
  2. A father and his wife strangled their eldest son because he had converted, aided in this parricide by another son and a friend.

In both cases, the intolerant religious practice has led men to adopt a violent attitude and against nature. Voltaire then proceeds to show, by analysis of history, that « fanaticism » and « violence » are synonymous.

It is well known that it has cost since that Christians argue about the dogma: the blood flowed, either on the scaffold or in battles, from the fourth century to the present. We confine ourselves here to wars and horrors that the quarrels of the Reformation were excited, and see what was its source in France. Perhaps a shortcut and fair view of so many calamities will open the eyes of some poorly educated, and well made touch hearts.  

Treatise on Tolerance on the occasion of the death of Jean Calas (1763) Voltaire

The rationale for intolerance derided

The massacres of Saint Bartholomew (1572) have led thousands of Huguenots (Protestants) in the Seine. Since then, the Catholic community fear Protestants reprisals. They therefore justify intolerance as a bulwark against those crazy mad « who pray to God in bad French. »

View original image
Massacre of St. Bartholomew in 1572

Voltaire is surprised by this type of reasoning, a priori very paradoxical, that is to say that the Huguenots were raised because we opprimions, so we must continue to oppress them to prevent them to raise again.

For Voltaire, manners have changed.

The lures of religions, fierce hatred between communities, have softened. Voltaire

It is time to try new ideas like that is to do good: benevolence. He shows, in fact, from example, that countries that have tried the sharp tolerance now in peace:

The inspired fury dogmatic spirit and abuse of mistaken Christianity has poured so much blood, has produced many disasters, Germany, England, and even in Holland than in France, however, today ‘ hui difference of religion does not cause any trouble in those states; the Jew, the Catholic, Greek, Lutheran, Calvinist on the Anabaptist, the Socinian, the Mennonite, the Moravian, and many others live as brothers in these lands, and also contribute to the good of society.

Treatise on Tolerance on the occasion of the death of Jean Calas (1763) Voltaire


The title of Chapter V seems rather curious. At the time however intolerance was obvious. It took a superhuman effort to reverse values.

Voltaire first shows that France is a mosaic of « sects »; Calvinists, Lutherans alongside Jews, Jansenists. For Voltaire, this multiplication of faiths is a chance. The more  they are, the more they lose importance. He gives the example of Roman or Greek polytheism, multiplying endlessly deities, for everything and anything, a new street, a well , vines and olive trees, and all was well in the best of worlds.

View original image
The Inquisition – image of intolerance

The advent of monotheism is inseparable intolerance.

Voltaire is also based on past examples to show that intolerance is not timeless: once again he uses irony :

The excommunication of grasshoppers and insects harmful to crops was very much in use. Voltaire

to show the absurdity of non-reflected dogmas. Today, he says, grasshoppers are left in peace!

Tolerance can therefore be accepted. Because it is necessary for the public peace. It allows the repatriation of expatriate talent. It allows the country’s prosperity.


Voltaire examines the argument advanced by the insane religions: Intolerance is natural (and therefore justifiable). It is interesting and could be used to justify racism. Remember the famous words of Goebbels:

Nature is cruel. We (the Nazis) therefore have the right to be as well. Joseph Goebbels

Goebbels was based on the theory of natural law (the law of the strongest), which makes the lion (the strong) eats the gazelle. There are no good. There is no harm. Only the laws of nature.

Voltaire shows that this principle necessarily leads to the annihilation of the human race:

If he were human right to behave well, so should the Japanese hated the Chinese, who would have abhorred the Siamese; it would continue Gangarides, that would fall on the people of the Indus; a Mogul would tear the heart in the first Malabar he would find; the Malabar could kill the Persian, which could kill the Turk: all together and throw themselves on the Christians, who have so long devoured each other.

Voltaire – Treatise on Tolerance on the occasion of the death of Jean Calas (1763)

This law can not be natural. Otherwise it would long that there would be no more humanity.


Voltaire continues to explore the past. Greece was studded with religious and philosophical currents. Yet each struggled free and at peace: the Stoics, Cynics, Epicureans, who denied the gods of the city. Yet if history is correct, he only lists a heresy trials: that of Socrates. Voltaire class yet this trial in the workbook of « disturbing public order ». Tolerance in Greece was therefore the rule.


He then passes the examination of Roman history. Again, he found that the Roman Empire, its universal character, was the home of many faiths, worshipers of Zoroaster (Iran), Jews, Assyrians in Iraq, Greeks … who lived in peace.

The Roman conquests were made in the name of fame, the lure of wealth, for the slaves they offered, not for religious issues. The country was conquered and absorbed with his gods! The Romans had no use of the Druids!

And Christians. Have they not persecuted? They were not torn by lions ? Martyrs? Does Voltaire holds a cons-example?


Voltaire think the stories about martyrs are very exaggerated. Many « tales » were invented to feed the legend of the first hours of Christianity and to attract new followers.

But if the Romans had so persecuted the Christian religion, if the Senate had killed so many innocent people by unusual punishments, if they had plunged into boiling oil Christians, if they had exposed the naked girls to the beasts in the circus, how could they all left in peace the first bishops of Rome? [..] So Let us arrange this tale with acrostics to sybils who predicted the miracles of Jesus Christ, and with so many parts assumed a false zeal lavished to abuse credulity.

Treatise on Tolerance on the occasion of the death of Jean Calas (1763) Voltaire


In this chapter, Voltaiere talk abaout the negative effects of false myths (like the Christian martyrs). A little curious mind will soon generalize: if the anecdote is false, then everything is wrong and God does not exist. Also, peddle a false legend can it be extremely detrimental to religion.


Voltaire wish here to show that the truths believed to timeless, are in fact deeply rooted in time. He takes example of the Virgin Mary:

There are no long as the immaculate conception is established: the Dominicans are not yet believe. In which time Dominicans-they begin to deserving punishment in this world and the next?

T reaty on Tolerance on the occasion of the death of Jean Calas (1763) Voltaire.

Volataire also shows the very unchristian behavior of the holiest Fathers of the Church, like the apostles and even Jesus himself, who prohibited eating the forbidden meat (the Jews) and respected the Sabbath.

If we have to learn from someone to lead us in our endless disputes, it is certainly the apostles and evangelists. There was to excite a violent schism between St. Paul and St. Pierre

Treatise on Tolerance on the occasion of the death of Jean Calas (1763) Voltaire.


Reading the Old Testament (Hebrew Bible or Pentateuch) is unequivocal. The Jewish God is characterized by intolerance, which starts from the beginning: he selects a « chosen » people. He gives him land. He gives him the right to kill indigenous (including the Amorites). The passage on the capture of Jericho is incredibly violent.

This God is jealous and does not like competition. If you believe Voltaire, Moses massacred 26,000 of these compatriots when he saw that they were worshiping golden calves.

This is what Voltaire said that

God do not punish a foreign cult, but a desecration of his, an indiscreet curiosity, disobedience, perhaps even a spirit of revolt. We feel that such punishments belong only to God in the Jewish theocracy. We can not complain too that these times and these morals have no relation to ours.

Treatise on Tolerance on the occasion of the death of Jean Calas (1763) Voltaire.

This confirms God’s jealousy.

Voltaire insists that God did not need men to do justice. Let him judge the behavior of each of the doomsday and, meanwhile, live together, as did the Jews, who tolerated sects with very different practices of the Jewish canon: the Essenes (sect who gave birth to Christians) the Sadducees, the Pharisees …


Voltaire read the New Testament and found no trace of intolerance: the New Testament was written to correct the excesses of the Old. To erase the indefensible passages? To leave transpire that justice and love? To present a more salable religion?

Intolerance was introduced into Christian dogma by the Church Fathers, like St. Augustine who justified the jihad (under certain conditions it is true).

If the passion of Christ must be an example for the Christian, then « be martyrs rather than murderers. »


Superstition is to religion what astrology is to astronomy, very mad daughter of a wise mother. Both girls have long captivated the whole earth.

Treatise on Tolerance on the occasion of the death of Jean Calas (1763) Voltaire.

Voltaire sees in « healthy » religion  a way to connect (religare in Latin) men and also to fill a void. Without religion, the vacant space would inevitably be filled by ideas, not always advisable.

When men do not sound notions of divinity, misconceptions replace them.

Treatise on Tolerance on the occasion of the death of Jean Calas (1763) Voltaire

Religion, practiced well, has its virtues. Superstition is the gangrene, the mockery. It leads men to say and do things contrary to these foundations: Christ is « love of neighbor ». The fanatic is soaked superstition. He ends up killing his neighbor in the name of Christ!

Voltaire find ridule to perish abaout theological questions: Does the father produced the son? Are they of the same substance? The host is she a symbol or the body of Christ? Thousands of men, by virtue also died to resolve such disputes.

Religion must never be imposed but chosen. An imposed religion is a contradiction in itself.


It is not to men that I speak; it’s you, God of all beings, of all worlds and of all time:

VOLTAIRE is good for men, denouncing, ironically, differences in religious practices that have trained for millennia, men against each other […] ..


Voltaire did not reject religion but superstitions surrounding it. These brought only discord and disturbance of public order. He wants to take you back to a healthy religion, free of insoluble existential questions (what is infinity?) To focus on virtue and especially tolerance, the sine qua non « living together ».