QUOTE : It is necessary to have metaphysical ideas-we cannot do without them-but it is also necessary to submit them very seriously to the test whether they agree with the human being: a good metaphysical idea does not spoil one's stomach. For instance, if I hold a metaphysical conviction that we live on after death for fifty thousand years instead of fifty million-if that is a solution-! try what it means if I believe in fifty thousand years only; perhaps that is good for my digestion-or bad. You see, I have no other criterion. Of course, it sounds funny, but I start from the conviction that man has also a living body and if something is true for one side, it must be true for the other. For what is the body? The body is merely the visibility of the soul, the psyche; and the soul is the psychological experience of the body. So it is really one and the same thing. Therefore, a good truth must be true for the whole system, not only for half of it. According to my imagination, something seems to be good-it f-its in with my imagination-but it proves to be entirely wrong for my body. And something might apparently be quite nice for the body, but it is very bad for the experience of the soul, and in that case I have a metaphysical enteritis. So I must be careful to bring the two systems together; the only criterion is that both are balanced. When life flows, then I can say it is probably all right, but if I get upset I know something must be wrong, out of order at least.<br /><br />Jung, C. G.. Nietzsche's Zarathustra: Notes of the Seminar given in 1934-1939. Two Volumes: 1-2, unabridged (Jung Seminars) (p. 355).