Now the business of ethics is to define its own subject-matter, that is to say the particular kind of manifold with which it deals, and the kind of unity of which that manifold is susceptible. But as I approach this first goal of my enterprise, there is one obstacle which I must try to remove out of the way of the reader, before I can hope to win him to a hospitable consideration of my conclusions. The jointness or inseparableness of the two acts out of which certainty or reality issues has created all the difficulties. The fact that the manifold must be regarded as remaining a manifold, unaltered in its character as such, not derivative from the One (there is no such One), and that the unity does not contrariwise result from the manifold in the sense of springing from or being derived from it;—in other words that we must see the same landscape of things and events both _sub specie pluralitatis_ and _sub specie unitatis_—has been the stumbling-block. The history of philosophy might be written under the two headings: 1, monistic systems that undertake, collapsing in their futile effort, to derive the world and its plurality from the One, as if there were such an One, out of whose bosom philosophy might evoke the many (creational systems, pantheistic systems, emanation systems, evolution systems); 2, pluralistic systems that essay, with equal lack of success, to explain the unity as somehow the offspring of the plurality. Why then have these systems flourished? Why are these vain undertakings still renewed? The reason is that we cannot understand the joint action of the two functions, and the very point where enlightenment is needed is for us to recognize that no fundamental truths can be understood by us, that we can only look at them, contemplate and accept them. The point, I say, where enlightenment is needed is that the habit of trying to understand is due to a prejudice, to what may be called the _superstition of causality_. I shall have to explain this hardy assertion with some care to prevent misconception. Causality, it will be objected, is the one thread that leads us through the labyrinth of nature. The search for causes enables us to become at home in our world by foreseeing events. In what sense then can it be permissible to speak of the prejudice of causality, nay, of the superstition of it? With what warrant prescribe a limit to the aspirations of the human intellect to push its inquiries to the farthest limit, even so far as to understand the functional finalities themselves, if such there be?