因明入正理論疏 3.4

3.4

As for the meaning of viruddha-hetu: it means that two pratijñās are mutually opposed. These four faults, without changing the other's hetu, can cause the proponent's pratijñā to become contradicted; because it acts as the hetu for the contradictory dharma, it is named viruddha-hetu. The hetu receives the name of its result, hence it is called 'contradictory'; it is not that the hetu contradicts the pratijñā and is therefore called contradictory, so there is no objection by parity that the pratijñā also contradicts the hetu. The Nyāyamukha states: 'If a dharma is capable of establishing the contradictory sādhya, it is the viruddha fault and is named a fallacious hetu (hetv-ābhāsa), just like an uncontradicted dharma. A contradictory one is likewise, because where the dharma to be established is absent, it is definitely absent.' On account of what it states, the hetu remains fixed as before, while the dṛṣṭānta may be changed and relied upon; therefore, of the four faults below, the first one changes the dṛṣṭānta, while the latter three remain as before.