因明入正理論疏 3.147

3.147

述曰：此示法。離者，不相屬著義。言諸無常者，即離常宗。見彼質礙，離無礙因。將彼質礙屬著無常，返顯無礙屬著常宗，故聲無礙定是其常。今既但云見彼無常、有質礙性，不見無常屬有礙性，即不能明無宗之處因定非有，何能返顯有無礙處定有其常？不令常、無礙互相屬著，故為過也。合即先合聲上無礙，欲令無礙、常住定隨；離即先離聲上常住，欲令無宗因定不有，返顯無礙之所至處，定有常住宗義隨逐。故《理門》云：「說因宗所隨，宗無因不有。依第五顯喻，由合故知因。」准此即是雙離宗、因，合應返此。

The Commentary states: This demonstrates the method. 'Separation' means the sense of not being connected. Stating 'whatever is impermanent' separates from the thesis of permanence. 'Is seen to possess corporeal obstruction' separates from the reason of non-obstruction. Connecting that corporeal obstruction to impermanence inversely shows that non-obstruction is connected to the thesis of permanence; thus, that sound is non-obstructed is definitely eternal. Now, merely saying 'is seen to possess the nature of impermanence and the nature of corporeal obstruction' without showing that impermanence is connected to the nature of corporeal obstruction fails to clarify that where the thesis is absent the reason is definitively absent; how could it inversely show that where non-obstruction exists, permanence definitely exists? Because it does not cause permanence and non-obstruction to be mutually connected, it is a fallacy. Application (upanaya) first applies [the reason] to the non-obstruction of sound, seeking to make non-obstruction and permanence invariably follow each other; separation first separates from the permanence of sound, seeking to ensure that where the thesis is absent the reason is definitively absent, inversely showing that wherever non-obstruction reaches, the thesis-property of permanence invariably accompanies it. Therefore the Nyāyamukha says: 'Stating that the reason is accompanied by the probandum, and that without the probandum the reason does not exist. Relying on the ablative case, the example is shown; through application, one knows the reason.' According to this, it is a double separation of thesis and reason, and application should be the reverse of this.