You should see through the śāstra, authoritatively śāstra, books. What we are speaking about the moon planet, sun planet, or God, His abode is Vaikuṇṭhaloka, spiritual world, so many things we are talking—how we are talking? We are talking through the Vedic literature. Because Vedic literature is authoritative. According to Vedic civilization, we don't accept any book written by rascal. We take, we accept the authority of the Vedas. What is stated there in the Vedas we accept, without any argument.
For example . . . there are many examples. One of the example is that the Veda says that if you touch the stool of an animal, even your own stool . . . that is the system. In India still they are . . . not in the city, but in the villages you will see even ordinary man, he goes to pass stool in the field, and just after passing stool he will take bath just to purify himself, change his cloth. That is the śāstric injunction. But in one place it is said that the stool of the cow is pure.
Now if you argue that, "One place you say that the stool of an animal is impure, even your own stool if you touch you have to take bath, how is that, another animal's stool is pure?" This is superficially contradiction. But those who are following strictly the Vedic principles, they will accept that the stool of cow, or cow dung, is pure. Now, if you argue, "Why it is pure?" then you come to a modern chemical analysis, and you will find the cow dung is full of antiseptic properties. It has been examined in Calcutta by one doctor, Raj Mohan Bose. Therefore, the Vedic injunction is so perfect.