This paper discusses the central issue posed by the question of whether adopting a position that can be characterized as liberal in the socio-political realm presupposes the assumption of a skeptical or relativist position in the realm corresponding to the foundations of normative ethics. Using the conception elaborated by Kant as an example, he argues in favor of the theory that a genuinely liberal position is not only incompatible with, but also, strictly speaking, can only be founded on a universalist and non-relativist position in the plane of normative ethics. On this basis, he offers reasons that make the idea plausible that far from being irreconcilable positions, liberalism and Catholicism aim rather towards a profound dimension of convergence from which the possibility arises for a dialog fruitful to both.