Coming to the principles, we find these Vedic thinkers very courageous and wonderfully bold in propounding large and generalised theories. Their solution of the mystery of the universe, from the external world, was as satisfactory as it could be. The detailed workings of modern science do not bring the question one step nearer to solution, because the principles have failed. If the theory of ether failed in ancient times to give a solution of the mystery of the universe, working out the details of that ether theory would not bring us much nearer to the truth. If the theory of all-pervading life failed as a theory of this universe, it would not mean anything more if worked out in detail, for the details do not change the principle of the universe. What I mean is that in their inquiry into the principle, the Hindu thinkers were as bold, and in some cases, much bolder than the moderns. They made some of the grandest generalizations that have yet been reached, and some still remain as theories, which modern science has yet to get even as theories. For instance, they not only arrived at the ether theory, but went beyond and classified mind also as a still more rarefied ether. Beyond that again, they found a still more rarefied ether. Yet that was no solution, it did not solve the problem. No amount of knowledge of the external world could solve the problem.