Social reformers like Gandhi and the members of very numerous societies in India today are making slow but sure progress in restoring the ancient values of caste, based solely on natural qualification and not on birth. Every nation on earth has its own distinctive misery-producing karma to deal with and remove; India, too, with her versatile and invulnerable spirit, shall prove herself equal to the task of caste-reformation.
"To a certain extent, all races and nations observe in practice, if not in theory, the features of caste. Where there is great license or so-called liberty, particularly in intermarriage between extremes in the natural castes, the race dwindles away and becomes extinct. The Purana Samhita compares the offspring of such unions to barren hybrids, like the mule which is incapable of propagation of its own species. Artificial species are eventually exterminated. History offers abundant proof of numerous great races which no longer have any living representatives. The caste system of India is credited by her most profound thinkers with being the check or preventive against license which has preserved the purity of the race and brought it safely through millenniums of vicissitudes, while other races have vanished in oblivion."
THIS ABOVE EXPLANATION IS FROM WORLD FAMOUS BOOK "AUTOBIOGRAPHY OF A YOGI" by Sri SWAMI PARAMAHAMSA YOGANANDA.
