Modern philosophy's and Benedict XVI's struggle with relativism
Relativism is a weird word as far as philosophy goes, because there are no relativist philosophers. Only your enemies are relativists: it is purely a term of abuse. Anglo-American philosophers attack French thinkers as relativists. The French reciprocate by attacking Anglo-Saxons as relativism-loving free-marketeers. The problem stems from the fact that all modern philosophies are "relationsims"; that is, philosophies of relations. So, everyone claims they have founded a proper science or logic of relations, and everyone condemns their opponents as mere relativists, whose empty philosophies depends upon nothing and, in an infinite regress, will ultimately sink into a void of meaninglessness. This, to cut through a longer argument, is Kant's contribution to modernity. It arises because of a fundamental relation – a super-relation – that Kant posits between humans and the world. Because we are condemned to be human, we can never know the world, but only our relation to it. After Kant, reason is limited and so we cease doing ontology (the study of what is) and turn towards epistemology (the theory of knowledge).
Benedictine philosophy sets out from Kant's idea of the limits of reason. As a theologian, he wants to supplement reason with true, Catholic faith. But speaking as a philosopher, he seems to be arguing rather differently: he seems to be saying that the limits of reason are an intrinsic weakness of reason. In fact, that reason is unstable and chaotic at heart. When he speaks of relativism, this is what he is talking about. He is not criticising the logic of, say, Saussurian semiotics, or of classical economics, nor even Einsteinian physics. He is saying that, ultimately, these and all other relation-based theories combine together to create a force. In theological terms he describes it as evil, but in philosophical terms is better described as a force tending towards chaos and destruction.
Here, Benedict is stepping beyond Kantian epistemology in order to make a return to ontology.