The Positive Sciences of the Ancient Hindus c10.96

c10.96

The scientific Methods already noticed—the Joint Method of Difference (the Pañchakáraṇí) and the Joint Method of Agreement (Vpáptigraha with Upádhisaṅkánirasa and Tarka)—are not the only methods of ascertaining causality or concomitance, or establishing a theory (सिद्धान्त); nor are these Methods always practicable. Very often we reach the explanation of a fact (उपपत्ति) by means of a hypothesis (कल्पना) properly tested and verified (निर्णीत). A legitimate hypothesis must satisfy the following conditions:—(1) the hypothesis must explain the facts (दृष्टसिद्धि or उपपत्ति); (2) the hypothesis must not be in conflict with any observed facts or established generalisations (दृष्टसिद्धये हि अदृष्टं कल्प्यते, न दृष्टविघाताय—Jayanta, Nyáyamañjarí, Áhnika 1); (3) no unobserved agent must be assumed where it is possible to explain the facts satisfactorily by observed agencies (यदि दृष्टदशन्तरेण दृष्टं न सिध्यति काममदृष्टं कल्प्यताम्, अन्यथाऽपि तदुपपत्तौ किं तदुपकल्पन्रेन *ibid.*); (4) when two rival hypotheses are in the field, a crucial fact or test (विनिर्गमक, *ratio sufficiens*) is necessary; the absence of such a test (विनिगमनाविरह) is fatal to the establishment of either; (5) of two rival hypotheses, the simpler, *i.e.* that which assumes less, is to be preferred, *ceteris paribus* (कल्पनालाघव *versus* कल्पनागौरव); (6) of two rival hypotheses, that which is immediate or relevant to the subject-matter is to be preferred to that which is alien or remote (प्रथमोपस्थितत्व); (7) a hypothesis that satisfies the above conditions must be capable of *verification* (निर्णय) before it can be established as a theory (सिद्धान्त). The process of verification of a hypothesis consists in showing that it can be deduced as a corollary from (or is involved by implication in) some more general proposition which is already well established (*cf.* Vatsyayana's exposition and illustration of Verification, निर्णय—including both the Deductive Method and Colligation).