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APPENDIX A
intermediary between the soul and the senses, since urged by the soul it betakes itself on each occasion to that sense through which the soul desires to perceive or to act. ... If it rests motionless in the soul, the union of the latter with the senses ends, and no perception or act or experience is possible. . . . If the organ of thought were omnipresent like the soul, or if the soul could enter into immediate relation with the objects of knowl. edge, all objects would be simultaneously perceived. As the organ of thought, on the one hand, imparts the quickening power to the soul, so, on the other, it acts as a kind of check by preventing the soul from exercising more than one function at the same time." 14
Nyāya, logic, the sixth of the classical systems, is attributed to a shadowy figure, Gautama-nicknamed Akşapāda, “the footeyed,” that is to say, "with his eyes fixed on his feet"-whose textbook, the Nyāya-sūtra, composed perhaps as early as 150 B.C.,16 but more probably between 200 and 450 A.D.,16 parallels the Vaiseșika in its atomic doctrine, cosmology, and psychology, but is devoted principally to the science of logic. Four sources of true knowledge are recognized: 1. perception (pratyakşa), 2. inference (anumāna), 3. analogy (upamāna), and 4. credible testimony (śabda). Inference, the sole reliable means to philosophical knowledge, is of three kinds: 1. inference from cause to effect (pūrvavat), 2. inference from effect to cause (seșavat), and 3. reasoning from perception to abstract principle (sāmányato dựsta). Three kinds of cause are recognized: 1. the material or inhering cause (upādāna-kāraṇa, samavāyi-kāraņa), e.g., in the case of a carpet, its threads; 2. the noninhering or formal cause (asamavāyi-kāraņa), in the case of the carpet, the arrangement and knotting of its threads; and 3. the effective or instrumental cause (nimitta-kāraņa): the weaver's tools. The syllogism of the Nyāya
14 Garbe, "Vaisesika," p. 570. 15 Garbe, “Nyāya," in Hastings, op. cit., Vol. IX, p. 428. 18 A. B. Keith, Indian Logic and Atomism, Oxford, 1921, p. 24.
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