contain Buddhist and Jaina philosophy
and the six systems of Hindu thought. These six systems of orthodox
Hindu thought are the Sa@mkhya, the Yoga, the Nyaya, the Vais'e@sika,
the Mima@msa (generally known as Purva Mima@msa), and the Vedanta (known
also as Uttara Mima@msa). Of these what is differently known as Sa@mkhya
and Yoga are but different schools of one system. The Vais'e@sika and
the Nyaya in later times became so mixed up that, though in early times
the similarity of the former with Mima@msa was greater than that
with Nyaya, they came to be regarded as fundamentally almost the
same systems. Nyaya and Vais'e@sika have therefore been treated

8

together. In addition to these systems some theistic systems began
to grow prominent from the ninth century A.D. They also probably
had their early beginnings at the time of the Upani@sads. But at
that time their interest was probably concentrated on problems
of morality and religion. It is not improbable that these were
associated with certain metaphysical theories also, but no works
treating them in a systematic way are now available. One of their most
important early works is the _Bhagavadgata_. This book is rightly
regarded as one of the greatest masterpieces of Hindu thought. It is
written in verse, and deals with moral, religious, and metaphysical
problems, in a loose form. It is its lack of system and method which
gives it its peculiar charm more akin to the poetry of the Upani@sads
than to the dialectical and systematic Hindu thought. From the ninth
century onwards attempts were made to supplement these loose theistic
ideas which were floating about and forming integral parts of religious
creeds, by metaphysical theories. Theism is often dualistic and
pluralistic, and so are all these systems, which are known as different
schools of Vai@s@nava philosophy. Most of the Vai@s@nava thinkers wished
to show that their systems were taught in the Upani@sads, and thus
wrote commentaries thereon to prove their interpretations, and also wrote
commentaries on the _Brahmasutra_, the classical exposition of the
philosophy of the Upani@sads. In addition to the works of these Vai@s@nava
thinkers there sprang up another class of theistic works which were of a
more eclectic nature. These also had their beginnings in periods as old
as the Upani@sads. They are known as the S'aiva and Tantra thought, and are
dealt with in the second volume of this work.

We thus see that the earli