An extract from the French writer and satirist Voltaire's Dictionnaire Philosophique.
It is clear that the individual who persecutes a man, his brother, because he is not of the same opinion, is a monster. That admits of no difficulty. But the government! but the magistrates! but the princes! how do they treat those who have another worship than theirs? If they are powerful strangers, it is certain that a prince will make an alliance with them. Franois I., very Christian, will unite with Mussulmans against Charles V., very Catholic. Francois I. will give money to the Lutherans of Germany to support them in their revolt against the emperor; but, in accordance with custom, he will start by having Lutherans burned at home. For political reasons he pays them in Saxony; for political reasons he burns them in Paris. But what will happen? Persecutions make proselytes? Soon France will be full of new Protestants. At first they will let themselves be hanged, later they in their turn will hang. There will be civil wars, then will come the St. Bartholomew; and this corner of the world will be worse than all that the ancients and moderns have ever told of hell.
Madmen, who have never been able to give worship to the God who made you! Miscreants, whom the example of the Noachides, the learned Chinese, the Parsees and all the sages, has never been able to lead! Monsters, who need superstitions as crows' gizzards need carrion! you have been told it already, and there is nothing else to tell you - if you have two religions in your countries, they will cut each other's throat; if you have thirty religions, they will dwell in peace. Look at the great Turk, he governs Guebres, Banians, Creek Christians, Nestorians, Romans. The first who tried to stir up tumult would be impaled; and everyone is tranquil.
Of all religions, the Christian is without doubt the one which should inspire tolerance most, although up to now the Christians have been the most intolerant of all men. The Christian Church was divided in its cradle, and was divided even in the persecutions which under the first emperors it sometimes endured. Often the martyr was regarded as an apostate by his brethren, and the Carpocratian Christian expired beneath the sword of the Roman executioners, excommunicated by the Ebionite Christian, the which Ebionite was anathema to the Sabellian.
This horrible discord, which has lasted for so many centuries, is a very striking lesson that we should pardon each other's errors; discord is the great ill of mankind; and tolerance is the only remedy for it.
There is nobody who is not in agreement with this truth, whether he meditates soberly in his study, or peaceably examines the truth with his friends. Why then do the same men who admit in private indulgence, kindness, justice, rise in public with so much fury against these virtues? Why? it is that their own interest is their god, and that they sacrifice everything to this monster that they worship....
...[T]oday when so many sects make a balance of power, what course to take with them? Every sect, as one knows, is a ground of error; there are no sects of geometers, algebraists, arithmeticians, because all the propositions of geometry, algebra and arithmetic are true. In every other science one may be deceived. What Thomist or Scotist theologian would dare say seriously that he is sure of his case?
If it were permitted to reason consistently in religious matters, it is clear that we all ought to become Jews, because Jesus Christ our Saviour was born a Jew, lived a Jew, died a Jew, and that he said expressly that he was accomplishing, that he was fulfilling the Jewish religion. But it is clearer still that we ought to be tolerant of one another, because we are all weak, inconsistent, liable to fickleness and error. Shall a reed laid low in the mud by the wind say to a fellow reed fallen in the opposite direction : "Crawl as I crawl, wretch, or I shall petition that you be torn up by the roots and burned?"
