anena hi granthena bhāṣyakṛtā kāraṇaśuddhijñānāt prāmāṇyaniścayaḥ spaṣṭamākhyātaḥ /
For by this passage, the Bhāṣyakāra has clearly stated that the ascertainment of validity [comes] from the knowledge of the purity of the cause.