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definition of a good reason They added two more aspects to it abādhita-visayatva or being uncontradicted and asatpratipaksatva or not being counterbalanced by an equally good reason on the contrary The Naiyāyikas, however, rejected the Buddhist notion of causality and essential identity as the only two grounds of Vyāptı The actual relations on which the vyāptı may rest can be diverse For example, in “Rūpavān i asāt", the hetu is not the effect of the Sadhya nor is there any identity or tādātnya between them
The Jainas rejected the three characteristics of the hetu proposed by the Buddhists as well as the five characteristics proposed by the Naiyáyikas Instead the Jaina logicians proposed that the hetu may be defined by a single characteristic which would be both necessary and sufficient This one characteristic of the hetu is its untenability in the absence of the sādhya (anyathānupapannatya or avinābhāva) 39 If this characteristic be absent, the presence of all the three characteristics mentioned by the Buddhists would still not suffice for a valid inference For example, in the inference "He is dark since he is the son of Maitri as are the other sons of Maitri", the three conditions are satisfied because the hetu Maitritanayatva is found in the Pakșa as also in the sapaksaikadeśa constituted by the other sons of Maitri while it is absent from the asapaksa constituted by all those who are not dark It may be noted that the consideration of such cases led to the Naiyãyıka definition of Vyaptı as anaupādluka or non-accidental relationship The Jaina logicians have thus put their finger on the heart of the matter if the humanity of any one is a sufficient ground for asserting his mortality, it is solely and wholly because no one can be human without being mortal The assertion of humanity is incompatible with the denial of mortality In the well known Buddhist argument which seeks to establish the impermanence of all things on the ground of their existence, it is obvious that there is no sapaksa, since all things are included in the paksa Thus it is the realization of a necessary contradiction between the assertion of the hetu and the denial of the sādhya which is the essence of logical deduction Particularly interesting is the Jaina
