The theory of the relations between states and churches is bound up with the theory of Toleratio, and on that suject the eighteenth century scarcely rose above an intermittend, embarrassed, and unscientific view. For religious liberty is composed of the properties both of religion and of liberty, and one of its factors never became an object of disinterested observation among actual leaders of opinion. They preferred the argument of doubt to the argument of certitude, and sought to defeat intolerance by casting out revelation as they had defeated the persecution of witches by casting out the devil. There remained a flaw in their liberalism, for liberty apart from belief is liberty with a good deal of the substance taken out of it. The problem is less complicated and the solution less radical and less profound.
The modern mind is merely a blank about the philosophy of toleration; and the average agnostic of recent times has really had no notion of what he meant by religious liberty and equality. He took his own ethics as self-evident and enforced them; such as decency or the error of the Adamite heresy. Then he was horribly shocked if he heard of anybody else, Moslem or Christian, taking his ethics as self-evident and enforcing them; such as reverence or the error of the Atheist heresy. And then he wound up by taking all this lop-sided illogical deadlock, of the unconscious meeting the unfamiliar, and called it the liberality of his own mind. Medieval men thought that if a social system was founded on a certain idea it must fight for that idea, whether it was as simple as Islam or as carefully balanced as Catholicism. Modern men really think the same thing, as is clear when communists attack their ideas of property. Only they do not think it so clearly, because they have not really thought out their idea of property.