Let us observe here, further, that since the mysterious and inscrutable "I" is surrounded with an equally mysterious and inscrutable universe, and since the _ego_ and the external world are linked together by indissoluble relations, we are introduced to certain alternatives as to origins. Either the universe or "nature" is a mere phantom conjured up by the _ego_, or the _ego_ is a product of the universe, or both are the result of some equally mysterious power beyond us and the material world. Neither of these suppositions is absurd or unthinkable; and, whichever of them we adopt, we are again introduced to what may be termed a religion as well as a philosophy. On one view, man becomes a god to himself; on another, nature becomes his god; on the third, a Supreme Being, the Creator of both. All three religions exist in the world in a vast variety of forms, and it is questionable if any human being does not more or less give credence to one or the other. Scientific men, even when they think proper to call themselves idealists, must reject the first of the above alternatives, since they cannot doubt the objective existence of external nature, and they know that its existence dates from a time anterior to our possible existence as human beings. They may hold to either of the others; and, practically, the minds of students of science are divided between the idea of a spontaneous evolution of all things from self-existent matter and force, and that of the creation of all by a self-existent, omnipotent, and all-wise Creator. From certain points of view, it may be of no consequence whether a scientific man holds one or other of these views. Self-existent force or power, capable of spontaneous inception of change, and of orderly and infallible development according to laws of its own imposition or enactment, which is demanded on the one hypothesis, scarcely differs from the conception of an intelligent Creator demanded on the other, while it is, to say the least, equally incomprehensible. It is, besides, objectionable to science, on the ground that it requires us to assume properties in matter and energy quite at variance with the results of experience. The remarkable alternative presented by Tyndall in his Belfast Address well expresses this: "Either let us open our doors freely to the conception of creative acts, or, abandoning them, let us radically change our notions of matter." The expression "creative acts" here is a loose and not very accurate one for the operation of creative power. The radical change in "our notions of matter" involves an entire reversal of all that science knows of its essential properties. This being understood, the sentence is a fair expression of the dilemma in which the agnostic and the materialist find themselves.