 There are four "varnas" but thousands of "jatis".The "jatis" are complex social groups that lack universally applicable definition or characteristic, and have been more flexible and diverse than was previously often assumed.Certain scholars of caste have considered "jati" to have its basis in religion, assuming that in India the sacred elements of life envelop the secular aspects; for example, the anthropologist Louis Dumont described the ritual rankings that exist within the "jati" system as being based on the concepts of religious purity and pollution.