(astika) religio-philosophical systems developed. They all accepted the
authority of the Vedas, although their interpretations differ on various points,
and include theistic, monistic, atheistic and dualistic views. None of these
systems however, ever attained the status of a dogmatic orthodoxy.
    Despite their differences these systems are regarded as complementary
aspects of one truth seen from differing points of view.
    Nothing is known of the actual or supposed founders of these schools and
their names are probably those of the schools rather than of individuals. Each
school has a specific Sutra attributed to the supposed founder.
  The six systems are usually coupled in pairs: Samkhya (based on
  intellectual knowledge) and Yoga (on control of the senses and inner
  faculties); the Vaisesika (the experimental point of view based on sensory
  experience) and the Nyaya (logical view based on dialectics); Vedanta
  (based on metaphysical speculation) and Mimamsa (deistic and ritualistic
  point of view based on the sacred texts). The second system of each pair is
  more a methodology than a metaphysical school. There are also other
  systems such as the Saiva Siddhanta lying outside the traditional six
    The three main unorthodox systems (nastika) are the Buddhist, Jaina and
Charvaka. The first two deny the authority of the Vedas but believe in some
kind of future life, while the materialist Charvakas deny both propositions.
The literal meaning of Samkhya is ‘enumeration’. It is a system of dualistic
realism attributed to the semi-mythical sage Kapila. The oldest extant
Samkhya text is the Samkhyakarika of lsvara Krishna (3rd or 4th century AD).
    Two ultimate eternal realities are recognised in this system—Spirit
(purusha) and Nature (prakriti). Prakriti is a single, all-pervasive, complex
substance which evolves in the world into countless different shapes. Its three
main constituents or the guna: sattva, rajas and tamas. Each guna has
distinct characteristics, which