Medieval Philosophy

by Peter S. Adamson

natural law emerges along with “rational creatures” and never changes thereafter (§5). But if natural law has to do with reason, and not revelation, then why draw such a strong link between natural law and Scripture? Of course, Gratian is writing about church law, so he wants to stress that Scripture does indeed have a distinctively legal kind of authority. But he does not seem to be saying that the deliverances of natural law can only be reached by turning to Scripture. Nor does he think that everything found in Scripture is part of the natural law (§6). Rather, he’s doing what he does best, by emphasizing agreement, in this case between natural and religious law. His example is well chosen. The golden rule may be found in the New Testament, but it is also something that humans could grasp without the benefit of revelation. Even then, God would be part of the story. After all, human reason itself is a divine gift, as far as Gratian is concerned. Thus, heathens too are drawing on a heavenly source when they discover and follow the natural law with no help from the Bible. Alongside the natural law, there is what Gratian calls “human law” (§1, quoting Isidore of Seville). This means any law set down by a human authority, whether secular or ecclesiastical. In addition, there are all the requirements and guidelines that fall under the heading of “custom.” How, then, does custom relate to human and natural law?5 One thing is clear: no human law or custom has force if it contrav...