Applied to metaphysics, this question also assumes another form. The Buddhist declares that we need not look for anything which brings unity in the midst of these phenomena, we ought to be satisfied with this phenomenal world. This variety is the essence of life, however miserable and weak it may seem to be; we can have nothing more. The Vedantist declares that unity is the only thing that exists; variety is but phenomenal, ephemeral and apparent. "Look not to variety," says the Vedantist, "go back to unity." "Avoid unity; it is a delusion," says the Buddhist, "go to variety." The same differences of opinion in religion and metaphysics have come down to our own day, for, in fact, the sum-total of the principles of knowledge is very small.
Metaphysics and metaphysical knowledge, religion and religious knowledge, reached their culmination five thousand years ago, and we are merely reiterating the same truths in different languages, only enriching them sometimes by the accession of fresh illustrations. So this is the fight, even today. One side wants us to keep to the phenomenal, to all this variation, and points out, with great show of argument, that variation has to remain, for when that stops, everything is gone. What we mean by life has been caused by variation. The other side, at the same time, valiantly points to unity.
Coming to ethics, we find a tremendous departure. It is, perhaps, the only science which makes a bold departure from this fight. For ethics is unity; its basis is love. It will not look at this variation. The one aim of ethics is this unity, this sameness. The highest ethical codes that mankind has discovered up to the present time know no variation; they have no time to stop to look into it; their one end is to make for that sameness. The Indian mind, being more analytical " I mean the Vedantic mind " found this unity as the result of all its analyses, and wanted to base everything upon this one idea of unity. But as we have seen, in the same country, there were other minds (the Buddhistic) who could not find that unity anywhere. To them all truth was a mass of variation, there was no connection between one thing and another.
I remember a story told by Prof. Max Muller in one of his books, an old Greek story, of how a Brahmin visited Socrates in Athens. The Brahmin asked, "What is the highest knowledge?" And Socrates answered, "To know man is the end and aim of all knowledge." "But how can you know man without knowing God?" replied the Brahmin. The one side, the Greek side, which is represented by modern Europe, insisted upon the knowledge of man; the Indian side, mostly represented by the old religions of the world, insisted upon the knowledge of God. The one sees God in nature, and the other sees nature in God. To us, at the present time, perhaps, has been given the privilege of standing aside from both these aspects, and taking an impartial view of the whole. This is a fact that variation exists, and so it must, if life is to be. This is also a fact that in and through these variations unity must be perceived. This is a fact that God is perceived in nature. But it is also a fact that nature is perceived in God. The knowledge of man is the highest knowledge, and only by knowing man, can we know God. This is also a fact that the knowledge of God is the highest knowledge, and knowing God alone we can know man. Apparently contradictory though these statements may appear, they are the necessity of human nature. The whole universe is a play of unity in variety, and of variety in unity. The whole universe is a play of differentiation and oneness; the whole universe is a play of the finite in the Infinite. We cannot take one without granting the other. But we cannot take them both as facts of the same perception, as facts of the same experience; yet in this way it will always go on.
Therefore, coming to our more particular purpose, which is religion rather than ethics, a state of things, where all variation has died down, giving place to a uniform, dead homogeneity, is impossible so long as life lasts. Nor is it desirable. At the same time, there is the other side of the fact, viz that this unity already exists. That is the peculiar claim " not that this unity has to be made, but that it already exists, and that you could not perceive the variety at all, without it. God is not to be made, but He already exists. This has been the claim of all religions. Whenever one has perceived the finite, he has also perceived the Infinite. Some laid stress on the finite side, and declared that they perceived the finite without; others laid stress on the Infinite side, and declared they perceived the Infinite only. But we know that it is a logical necessity that we cannot perceive the one without the other. So the claim is that this sameness, this unity, this perfection " as we may call it " is not to be made, it already exists, and is here. We have only to recognise it, to understand it. Whether we know it or not, whether we can express it in clear language or not, whether this perception assumes the force and clearness of a sense-perception or not, it is there. For we are bound by the logical necessity of our minds to confess that it is there, else, the perception of the finite would not be. I am not speaking of the old theory of substance and qualities, but of oneness; that in the midst of all this mass of phenomena, the very fact of the consciousness that you and I are different brings to us, at the same moment, the consciousness that you and I are not different. Knowledge would be impossible without that unity. Without the idea of sameness there would be neither perception nor knowledge. So both run side by side.(From Lectures and Discourses- CW VOL.1)