In his book The Rise of the Modern Paganism, Peter Gay states that

“Relativism, Eclecticism, and toleration are so intimately related that they cannot be strictly separated even in thought. Relativism is a way of looking at the world, recognizing that no single set of convictions has absolute validity; Eclecticism is the philosophical method consequent on relativism—since no system has the whole truth, and most systems have some truth, discriminating selection among systems is the only valid procedure. Toleration, finally, is the political counterpoint of this world view and this method...”

This is the view developed in the Enlightenment. There is truth, but it is scattered throughout different ideas, systems, and world views. This knowledge is to be pursued through criticism and debate in an open forum. In our contemporary, post-modern world, relativism dictates that the various world views are either equally true or that there is no absolute truth (and I would argue that these two positions are equivalent). Contemporary tolerance is not based around a search for truth but a denial of its existence or at least the possibility of finding it.