The Nyaya school, one of the six schools of ancient Hindu philosophy, has a foundational book called the Nyaya Sutras.
The philosopher Gautama is said to have penned the Nyaya
Sutras, although Vatsyayana wrote the most important commentary in the fourth
century.
The Nyaya Sutras begin with an explanation of the reason of
human bonding, which is presented as a five-part causal chain including pain,
birth, activity, flaw, and erroneous belief.
Each of these components is caused by the one before it, and
is removed when its cause is destroyed.
The core cause of enslavement and rebirth (samsara) is
therefore incorrect beliefs, which must be changed in order to achieve complete
soul emancipation (moksha).
The Nyaya Sutras pay special emphasis to the pramanas, or
ways by which human beings might receive real and accurate knowledge, as well
as the norms and processes for applying them, in their search for proper
understanding.
Perception (pratyaksha), inference (anumana), analogy
(upamana), and authoritative witness are four such pra manas described in the
Nyaya Sutras (shabda).
The Nyayas' greatest contribution to Indian philosophy is
their concepts, which are acknowledged by practically all Indian philosophical
systems.