Smoke, Mist, and the Hill
In a Nyaya class at a Patna college, the teacher writes on the board: 'The hill has fire, because it has smoke.' A student, Rohan, says he saw a grey column rising from the hill at 6:30 a.m. and concludes fire. Another student, Sana, objects: it rained at 5 a.m.; the hill is 200 metres from a steam-emitting factory; the grey column could be mist or steam. The teacher asks the class to decide whether Rohan's inference is valid, which pramanas are involved, and what would make the inference sound. The class has a chart of Nyaya fallacies but no internet. The teacher insists on distinguishing 'valid inference' from 'true conclusion' and on stating the required vyapti.
1. Identify the pramanas Rohan and Sana are using and the vyapti needed for the inference.
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Rohan uses pratyaksha (perception of a grey column) and anumana (inference). Sana uses pratyaksha (rain, factory) and perhaps shabda if she cites the factory's schedule. The vyapti needed is: wherever there is smoke of the kind produced by combustion, there is fire. But the inference also needs the paksha, the hill, to actually possess the hetu, smoke. If the grey column is mist or steam, the hetu is not established. So the argument's success depends on establishing both the hetu and the invariable concomitance.
2. Test the inference for asiddha, savyabhichara, and badhita hetu, given the mist/steam possibility.
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Asiddha: the hetu 'smoke' is not established; it may be mist or steam, so the reason is not present in the paksha as required. Savyabhichara: even if it is smoke-like, the hetu may occur without fire, as with factory steam, so the vyapti is not invariable. Badhita: if another pramana established that the hill has no fire, the inference would be blocked; Sana's observations do not yet establish no fire, but they weaken the hetu. The inference is therefore not valid as stated. The conclusion may be true, but the argument does not establish it.
3. Revise the argument so it meets Nyaya standards, and explain what further observation or testimony would help.
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Revise: 'The hill has fire, because it has smoke of the kind produced by burning wood, observed closely and not explicable as mist or factory steam.' This requires a stronger hetu and a vyapti supported by prior observation. Further steps: observe colour and smell, check the factory's steam schedule, ask witnesses (shabda), and look for ash or burnt patches. Nyaya does not demand certainty beyond what the pramanas provide, but it does demand that the hetu be established and the vyapti unblemished.