can be known about them, to correlate them, to unify them, to insert them into a system. When we say, 7. The Interrelation of Sciences. however, as we did before, that there are separate sciences, we do not wish to be understood as meaning that these sciences are absolutely distinct from each other, that their respective facts are to be studied apart from all other phenomena in the world. This is not the case. The world presents itself to us as one, as a unity, a concrete whole. The mind splits it up into parts, but these parts are by no means really separate, independent entities. No phenomenon can be thoroughly understood in isolation, apart from all other phenomena. Strictly speaking, we cannot know one fact without knowing them all. "To know one thing thoroughly," as Professor James says, "would be to know the whole universe. Mediately or immediately, that one thing is related to everything else; and to know all about it, all its relations need be known."1 Tennyson expresses the same idea poetically in the oft-quoted lines : — "Little flower-but if I could understand What you are, root and all, and all in all, 1 See Leibniz, Monadology, § 61: "Everybody is affected by everything that happens in the world, so that a man seeing everything would know from each particular object everything that takes place everywhere, as well as what has taken place and will take place; he perceives in the present that which is remote in time and space." Cf. Paulsen, Introduction to Philosophy, translated by Frank Thilly, pp. 145 ff. Sciences And as the world is one, science is one. depend upon each other, are subservient to each other. Thus the facts of psychology are in some way related to the facts of physiology and physics; we cannot study the phenomenon of sensation without referring to the functions of the nervous system and the properties of matter. 8. Ethics and Psychology. Inasmuch as the facts of ethics are not isolated and independent, but are connected with the rest of the world, it is natural that the science of ethics should stand in some relation to the other sciences. If ethics is concerned with human beings, it will necessarily have something to do with the science of human nature. If ethics has to examine the conduct of man, and if conduct is not merely physical movement, but the outward expression, or sign, or aspect, of states of consciousness, and if the important thing in ethics is the fact that human beings judge of things in a certain way, then, of course, ethics is bound to depend, in a large measure, upon psychology. Psychology analyzes, classifies, and explains states of consciousness. Although all such states are of interest to the moralist, some of them require especial attention from him. The so-called ethical sentiments, the feeling of obligation, etc., are mental phenomena, and as such must be analyzed and explained by him; and they cannot be treated apart from the rest of consciousness. Thus, when the ethicist analyzes and describes the conscience, he is doing the work of the psychologist. And when he studies the moral nature of the infant and the primitive man, as he sometimes does, with a view to tracing the development of the conscience, he is still within the field of psychology. He may likewise consider animal states of consciousness, and search for the beginnings of conscience there, as Darwin did, in which case he is pursuing a psychological investigation. Indeed, we may say that in so far as ethics deals with moral states of consciousness, it is simply a special branch of psychology. But our science does not only look at the subjective side of conduct, it investigates the objective side also, and the relation which this bears to the subjective. What, it asks, is the nature of the acts which are judged moral; do they possess some mark or characteristic that makes them moral or leads men to call them so? Why do men judge as they do; what is the ground of moral distinctions? Why is wrong wrong, and right right? Explain the virtues and duties, e.g., benevolence, charity, justice, veracity, etc., and their opposites. Is there a standard or criterion or ideal by which conduct is judged, and what is it? Can we justify this standard or ideal, or is it something that cannot or need not be justified? Given a certain ideal or 1 See, for example, Ladd's treatment of the ethical sentiments in his Psychology, Descriptive and Explanatory, and Sully's account of the ethical or moral sentiments in the second volume of his Human Mind, or, in fact, any modern work on psychology. standard, what conduct is moral, what immoral? Does humanity remain true to the ideal? What is the highest good for man, the end of life? Can we specify it scientifically, or is it impossible to do so? Such are some of the questions which our science asks and seeks to answer. Should it be said that these also are problems for psychology to solve, we should raise no serious objection. The important thing is that the phenomena in question be examined and explained; whether by psychology or a special science does not matter. Ethical facts are, to a great extent, mental processes, and as such objects of psychological study. But the same may truthfully be said of the data of æsthetics. A science must thoroughly explain its facts, and, strictly speaking, psychology would have to explain ethical and æsthetical facts. But sciences divide their labor, and it is in keeping with the practices of modern scientific research that psychology should hand over to a special discipline the consideration of a particular set of its facts. Besides, there are certain questions, as we have just seen, which are not usually considered by the psychologist. The psychologist studies states of consciousness as such; he regards his work as completed when he has analyzed psychical phenomena and has referred them to their necessary psychical, or, if he be physiologically inclined, psychophysical antecedents. He does not, as a rule, inquire into the principles underlying conduct; he does not concern himself with the question, What is the end of life, or what is the standard or criterion by which acts are measured? But he could do so and still remain within the confines of his proper field of study. Such an investigation would surely assist him in better understanding the workings of the human mind, just as a knowledge of physics and chemistry would enable the physiologist better to understand the subject-matter of his science.1 9. Ethics and Politics. The relation which ethics bears to the science of politics largely depends upon our conception of the nature and function of these two sciences. If we assume with Plato that ethics is the science of the highest good, and that the object of the State is to realize that end, then politics depends upon ethics, for we cannot tell what the State ought to do until we know what the highest good is. But if the State is the highest good, then conduct has value only in so far as it subserves the interests of the State, and ethics is simply a branch of, or another name for, politics, as Aristotle declares. But let us say, ethics is the science of right and wrong; it discovers the principles of conduct, shows the ground of moral distinctions. Politics has to do 1 With the view advanced above Münsterberg, Der Ursprung der Sittlichkeit, and Simmel, Einleitung in die Moralwissenschaft, agree. See also Sully, The Human Mind, Appendix L. Mackenzie, A Manual of Ethics, especially Appendix B, opposes the concep |