Many of the more modern Upanishads appear to be the compositions of single authors and may be called tracts or poems in the ordinary European sense.  But the older ones, unless they are very short, are clearly not the attempts of an individual to express his creed but collections of such philosophical sayings and narratives as a particular school thought fit to include in its version of the scriptures.  There was so to speak a body of philosophic folk-lore portions of which each school selected and elaborated as it thought best.  Thus an apologue proving that the breath is the essential vital constituent of a human being is found in five ancient Upanishads[174].  The Chandogya and Brihad-Aranyaka both contain an almost identical narrative of how the priest Aruni was puzzled and instructed by a king and a similar story is found at the beginning of the Kausihtaki[175].  The two Upanishads last mentioned also contain two dialogues in which king Ajatasatru explains the fate of the soul after death and which differ in little except that one is rather fuller than the other[176].  So too several well-known stanzas and also quotations from the Veda used with special applications are found in more than one Upanishad[177].

The older Upanishads[178] are connected with the other parts of the Vedic canon and sometimes form an appendix to a Brahmana so that the topics discussed change gradually from ritual to philosophy[179].  It would be excessive to say that this arrangement gives the genesis of speculation in ancient India, for some hymns of the Rig Veda are purely philosophic, but it illustrates a lengthy phase of Brahmanic thought in which speculation could not disengage itself from ritual and was also hampered by physical ideas.  The Upanishads often receive such epithets as transcendental and idealistic but in many passages—­perhaps in the majority—­they labour with imperfect success to separate the spiritual and material.  The self or spirit is sometimes identified in man with the breath, in nature with air, ether or space.  At other times it is described as dwelling in the heart and about the size of the thumb but capable of becoming smaller, travelling through the veins and showing itself in the pupil:  capable also of becoming infinitely large and one with the world soul.  But when thought finds its wings and soars above these material fancies, the teaching of the Upanishads shares with Buddhism the glory of being the finest product of the Indian intellect.

In India the religious life has always been regarded as a journey and a search after truth.  Even the most orthodox and priestly programme admits this.  There comes a time when observances are felt to be vain and the soul demands knowledge of the essence of things.  And though later dogmatism asserts that this knowledge is given by revelation, yet a note of genuine enquiry and speculation is struck in the Vedas and is never entirely silenced throughout the long procession of Indian writers.  In well-known