athāsiddhatādidoṣaduṣṭaṃ sādhanam tadaivaṃvidhaviśeṣaṇopādāne 'pi na sādhyasiddhirastīti sarvathā vyarthameva viśeṣaṇam
If, on the other hand, the reason is defective due to being 'unproven' and the like, then even with the introduction of such qualifying epithets, the desired conclusion cannot be established; hence in every way the qualification is entirely useless.