Professor Höffding says that ethics "starts from its own assumptions" (p. 111). Ethics should not start from any assumptions.
If we are to come to a mutual understanding we must drop all subjectivism, we must not study ethics from special points of view, from the principles or standards of any individual or group of individuals. There is not the slightest use of a person making himself any "highest and only aim" which, it may be true, "from his point of view can never be refuted." So long as ethics starts from assumptions or principles, it will be no science; for truly, as Professor Höffding says in excuse of the inability to prove principles, "The difficulty always occurs in the enunciation of a principle that a direct demonstration of its validity cannot be given."
The requirement of ethics is to arrive at statements of fact. Let us build upon facts and we shall stand upon solid ground.
Ethics in order to be scientific must be based upon the objective and unalterable order of things, upon the ascertainable data of experience, upon the laws of nature.
Professor Höffding says:
"Religious ethics is founded on authority. Its contents are the revealed commands of authority; the feeling which impels us to pass ethical judgments is the fear or reverence or love with which men are filled in the presence of divine authority."
Scientific ethics can in this respect not be different from religious ethics, for it is also based upon authority. A scientific ethicist has to proceed like any other naturalist; he must observe the course of events and attempt to discover the laws in accordance with which the events take place. These laws are no less unalterable than any other natural laws, and we may appropriately call them the natural laws of ethics. The moral commands of ethical teachers have been derived, either instinctively or with a clear scientific insight, from the natural laws of ethics. The authority of the natural laws of ethics has been decked out by different religious teachers with more or less mythological tinsel or wrapped in mystic darkness; for practical purposes it remained to some limited extent the same and will to some extent always remain the same, for we shall have to obey the moral law, be it from fear, or reverence, or love.
The unity of all the ethical problems will be preserved, however much they may be differentiated. Indeed Professor Höffding in his enumeration sufficiently indicates their interconnection. He speaks of (1) the motive principle of judgment, (2) the test-principle of judgment, and (3) of the motive to action. Whatever difference he makes between these three terms, it is obvious that whether and how far judgments, tests, or motives are sound will depend upon their agreement with the authority of the natural law of ethics. The pedagogic problem is also connected with the ethical problem because upon our solution of the latter will directly depend the aim and indirectly also the method of education. Such complex motives as "ambition or the instinct of acquisition" will become "the means of attaining to true ethical self-assertion" in the degree proportional to the elements they contain which will strengthen our efforts of setting us at one with the natural law of ethics.
To sum up: The natural law of ethics has to be derived from facts like all other natural laws. The natural law of ethics is the authority upon which all moral commands are based, and agreement with the natural law of ethics is the final criterion of ethics.