Voltaire on Fanaticism

Voltaire on fanaticism:

Fanaticism is to superstition what delirium is to fever and rage to anger. The man visited by ecstasies and visions, who takes dreams for realities and his fancies for prophecies, is an enthusiast; the man who supports his madness with murder is a fanatic …
[…]
The only remedy for this epidemic malady is the philosophical spirit which, spread gradually, at last tames men’s habits and prevents the disease from starting; for, once the disease has made any progress, one must flee and wait for the air to clear itself. Laws and religion are not strong enough against the spiritual pest; religion, far from being healthy food for infected brains, turns to poison in them …
[…]
Even the law is impotent against these attacks of rage; it is like reading a court decree to a raving maniac. These fellows are certain that the holy spirit with which they are filled is above the law, that their enthusiasm is the only law they must obey.

What can we say to a man who tells you that he would rather obey God then men, and that therefore he is sure to go heaven for butchering you?

Voltaire, Philosophical Dictionary, from The Portable Enlightenment Reader

Meanwhile, almost 300 years later, life goes on much the same.