All the religious thought of the Vedic period can be found in the Upanishads (the literal meaning of this name is, sessions or assemblies of pupils round their master). There is not what could be called a philosophical system in these Upanishads; they are fragments, and are in the true sense of the word, guesses at truth; the spirit of the work is liberal, all shades of opinion are represented in it, the most divers, and sometimes contradictory. Conjectures abound with regard to the creation, all start from the theory that the world we see is not the true world, and that before it appeared there was the true Self--the Self-existent--the One which underlies the whole world, from which has come all that seems to exist and does actually exist. This was the final solution of the search after the Unknown, the Invisible, which had been foretold through a long chain of centuries; an intuition more convincing than all the arguments which were used at a later period to prove the existence of the Causa Causæ. The difficulties of the Brahmans in making a complete collection of these vague presentiments, confused thoughts, and true intuitions, were increased a hundredfold by the fact that they had to accept every word and every sentence of the Upanishads as supernaturally revealed. However contradictory at first sight, all that was said in the Upanishads had to be accepted and explained. It would seem difficult to construct a well-arranged literary monument out of such heterogeneous materials; but it was harmonised and welded into a system of philosophy that for solidity and unity will bear comparison with any other system of philosophy in the world.[117] This gigantic work, which commenced with the Vedic hymns and ended in the book called the Vedanta, or End, and was the end or supreme object of the Veda, is also known under the name of Mîmâmsâ-sutras. Mîmâmsâ is a desiderative form of the root _man_, to think, and a very appropriate name for a philosophical work of this kind; and sûtra means literally a string; but it is here used as the name of short and abstract aphorisms, rendered still more enigmatical by the conciseness of the language. There are several hundreds of these sayings or headings, forming tables of contents, a magic chaplet of immeasurable length, each word containing condensed thought. This work must have required a concentration of mind which it is difficult for us to realise. The meaning and form of these aphorisms are characteristic--here is one. “I will declare in a line, that which has required millions of volumes. “Brahma is true, the world is false; the soul is Brahma and nothing else.”