Then, again, the proof has been given by even those who are well-conversant with the scriptures themselves, for we have heard that the ordinances of the Vedas disappear gradually in every successive cycle. The duties in the Krita age are of one sort. Those in the Treta are of another sort, and those in the Dvapara are of a different sort. The duties in the Kali age, again, are entirely of a different character. It seems, therefore, that duties have been sanctioned for the respective cycles according to the powers of human beings in the different ages.