Vico discerned in Descartes' method for conducting right reasoning in the sciences a new and completely modern conception of human knowledge. This conception excludes those fields of study that the ancients believed to be the basis of civil wisdom, namely, eloquence or rhetoric and jurisprudence or law. Vico reminds us that what philosophy was for the Greeks, jurisprudence was for the Romans. In accordance with the Digest, Vico held that Roman law is civil wisdom itself: all that is necessary for proper human conduct is specified in the law. The law itself must be reasonable and just. The law, or jurisprudence, teaches us the principles of moral philosophy. The art of prudence in human affairs, which is the center of moral philosophy, is learned from the art of jurisprudence.
Donald P. Verene,
Vichian Moral Philosophy: Prudence as Jurisprudence,
Chi.-Kent L. Rev.
Available at: https://scholarship.kentlaw.iit.edu/cklawreview/vol83/iss3/3