The trend in the philosophy of law since the Enlightenment has been toward positivism, which emphasizes cultural tradition and present-day consensus. Both result in a relative or shifting determination of law. Consensus itself, democratically determined law, is prone to shift with politics. There is an alternative, however. The ancient concept of natural law claims a universal morality that is supposedly inherent in humanity or possibly the cosmos itself. It seems to offer some certitude, but does it really?

In any event, the two forms are coalescing. Natural law now leans heavily in the naturalistic direction of positivism, and positivism, by admiring tradition, admires natural law because natural law established Western legal tradition. Further, positivism itself admits of certain morality, albeit unconsciously or disingenuously. Consensus, therefore, is viewed as an expression of natural law by natural law adherents and essentially by positivists as well. These philosophies of law are synthesizing, but natural law is the more dominant of the two. It holds the commanding position. International law tends toward natural law. And Vatican doctors are the jurists of it.