In the certainty of conviction which the Sankhya doctrine opposed to the orthodox system, in the clearness with which it drew out the consequences of its point of view, in the boldness of scepticism concerning the gods and revelation, in the courage with which it protested against the regulations of the priests, and the whole religious tradition of the people, lies its importance. By following the rules of the Veda, so said the adherents of this philosophy, no peace can be obtained; the means prescribed by the Veda are neither pure nor of sufficient efficacy. How could it be a pure act to shed blood?--how could sacrifices and ceremonies be of sufficient force? If they really conferred the blessing of heaven, it could only be for a short time; the blessing would merely last till the soul assumed a new body. Temporal means could not give any eternal liberation from evil. The adherents of Kapila explained the gods, including Brahman, to be souls, not much distinguished from the souls of men; the more advanced denied their existence altogether. There was no supreme soul, they said, and no god. Even if there were a god, he must either be free from the world, or connected with it. He cannot be free, for in that case nothing would move him to creation, and if he were connected with the world he would be limited by it, and could not be omniscient.[382] Thus not only were the whole doctrine of Brahman and the whole system of gods overthrown, but the authority of the Veda was annihilated on which the Brahmans founded their belief no less than the worship by sacrifice, and with it all revelation, all the positive basis of religious life. The doctrine of Kapila found adherents. From orthodox scholasticism the Indian philosophy very rapidly arrived at rationalism and scepticism, though the latter, like the correct system, moved in scholastic forms and ended with an unsolved dualism. While in this manner one constructive system superseded the other, the formal side of knowledge did not remain without a keen and penetrating examination. The objects and means of knowledge were tested; men occupied themselves with fixing the categories of the idea, of doubt, of contradiction, of fallacies, of false generalisation, and conversion; and at last inquiries were made into the syllogism and the members of it, and more especially into the categories of cause and effect. Researches of this kind quickly grew into a system, the Nyaya or logic, which chiefly used the results of the theory of knowledge to establish the authority of the Veda, and overthrow the arguments brought against the revelation of it.[383] In themselves, at any rate in the late form in which we have them, the logical researches of the Indians are scarcely behind the similar works of modern times in the acuteness and subtilty of their categories.