Note 189 — Chapter XI · THE KINDS OF LEGAL RIGHTS.

There is another use of the term imperfect duty which pertains to ethics rather than to jurisprudence, and must be distinguished from that adopted in the text. According to many writers, an imperfect duty is one of such a nature that it is not fit for enforcement, but ought properly to be left to the free will of him whose duty it is. A perfect duty, on the other hand, is one which a man not merely ought to perform, but may be justly compelled to perform. The duty to give alms to the poor is imperfect; that of paying one’s debts is perfect. Perfect duties pertain to the sphere of justice; imperfect to that of benevolence. The distinction is not equivalent to that between legal duties and those which are merely moral. A duty may be a perfect duty of justice, although the actual legal system takes no notice of it; and conversely an imperfect duty of benevolence may be unjustly made by law the subject of compulsion. It does not seem possible, however, so to divide the sphere of duty by a hard and fast line. One of the most noteworthy attempts to do so is to be seen in Spencer’s Principles of Ethics.