By its differences from some objects and its likenesses to others; otherwise I could not know it. You cannot think of unity until you have seen variety; you cannot recognise likeness until you have seen unlikeness. The characteristic of intellectual evolution is the discrimination of differences followed by the recognition of likenesses; thus the intellect recognises object after object, each of them by its own characteristic marks. Analysis precedes synthesis. Differences are seen before an underlying unity is recognised. As this intelligence develops, we find the recognition of the Self and the Not-Self giving rise to struggle all over the world, social struggle as well as mental struggle. In every civilisation in which the intellect is developing from its earlier stages, you must have struggle without in order to stimulate the evolution within; it is a necessary stage, although it be a passing one, and it need not distress us, who see its end, in a world guided by the Gods. All the stages through which a nation passes are necessary for its growth, and need not be condemned merely because of their being limited and imperfect. In practical politics condemnation is useful as a stimulus, as one of the agents for bringing about the evolutionary changes, but the philosopher should understand, and, understanding, he cannot condemn. The worst struggle that we may see, the most terrible poverty, the most shocking misery, the strife of man against man and nation against nation--all these are working out the Divine purpose, and are bringing us towards a richer unity than without them we could possibly attain.