All doctrines relating to the creation of the world, the government of man by superior beings, and his destiny after death, are conjectures which have been given out as facts, handed down with many adornments by tradition, and accepted by posterity as "revealed religion". They are theories more or less rational which uncivilised men have devised in order to explain the facts of life, and which civilised men believe that they believe.
As a single atom man is an enigma: as a whole he is a mathematical problem. As an individual he is a free agent, as a species the offspring of necessity.
If Christianity were true religious persecution would become a pious and charitable duty: if God designs to punish men for their opinions it would be an act of mercy to mankind to extinguish such opinions. By burning the bodies of those who diffuse them many souls would be saved that would otherwise be lost, and so there would be an economy of torment in the long run. It is therefore not surprising that enthusiasts should be intolerant.