Ethics in ancient times signified moral philosophy (philosophia
moralis) generally, which was also called the doctrine of duties.
Subsequently it was found advisable to confine this name to a part
of moral philosophy, namely, to the doctrine of duties which are not
subject to external laws (for which in German the name Tugendlehre was
found suitable). Thus the system of general deontology is divided into
that of jurisprudence (jurisprudentia), which is capable of external
laws, and of ethics, which is not thus capable, and we may let this
division stand.