Therefore Kṛṣṇa says, ṛṣibhir bahudhā gītam. Then which one we have to accept? We have to accept... That is stated in the Vedic literature. Nāsau ṛṣir yasya mataṁ na bhinnam. Śrutayo vibhinnāḥ. Vedic literature—Sāma, Yajur, Ṛg, Artharva—they are different. They are one, but we understand differently, according to our quality of understanding. Otherwise, all Vedic literature aims to understand Kṛṣṇa. Vedaiś ca sarvair aham eva vedyaḥ (BG 15.15). That is the purpose of Veda, to understand Kṛṣṇa. After many, many births of studying of Vedic literature, in the process of jñāna-mārga, when one becomes actually wise, bahūnāṁ janmanām ante (BG 7.19), when he is actually wise, jñānavān māṁ prapadyante, he understands Kṛṣṇa and surrenders unto Him. That is actually understanding. So chandobhir vividhaiḥ pṛthak.
But Śrī Kṛṣṇa, Bhagavān, is specially referring herewith, brahma-sūtra-padaiś caiva. Brahma-sūtra means Vedānta-sūtra. Vedānta-sūtra He's referring. That is approved. There are different philosophical ways: parāmaṇu-vāda, nirviśeṣa-vāda, saviśeṣavāda, māyāvāda. They are all rejected. Simply brahma-sūtra padaiś caiva hetumadbhir viniścitaiḥ (BG 13.5). Brahma-sūtra means Vedānta-sūtra. It is called Brahma-sūtra because the first aphorism of Vedānta-sūtra is athāto brahma jijñāsā: "This human life is meant for inquiry about Brahman, the Absolute Truth." That is human life. Therefore it is called Brahma-sūtra. What is Brahman. Athāto brahma jijñāsā. Janmādy asya yataḥ. Janmādy asya yataḥ: (SB 1.1.1) "Brahman is the supreme source of everything."