Every senses, all sense, they are imperfect. You cannot see. You are seeing the sun, but what you are seeing? You are seeing just like a disc. But it is fourteen thousand times bigger than this planet. So your this naked sense perception has no value. Don't try to gather knowledge through these naked senses. Try to gather knowledge just like how creation is made. And that is stated here by the authorities, Kapiladeva. And if you take it, then your knowledge is perfect. And if you imagine, "Perhaps there was a chunk, and there was this, there was that"—all nonsense. At least we, Kṛṣṇa conscious men, we don't accept this nonsensical proposition. Our knowledge is derived-tad-vijñānārthaṁ sa gurum eva abhigacchet (MU 1.2.12). This is Vedic injunction. "If you want to know perfectly, if you want to have perfect knowledge," tad-vijñānārthaṁ sa gurum eva, "you must approach guru." Here is guru, Kapiladeva, or Kṛṣṇa, God. God is guru, original guru. God gave lessons to Brahmā. Brahmā gave lessons to Nārada. Nārada gave lessons to Vyāsadeva. Vyāsadeva gave lessons to us. This is Vyāsadeva's contribution. And if you follow this disciplic succession, then you get perfect knowledge. Otherwise, if you speculate, then you are in darkness, tamasi. What power you have got? All your senses are imperfect. How you can get perfect knowledge? That is not possible. Therefore the injunction is, tad-vijñānārthaṁ sa gurum evābhigacchet: (MU 1.2.12) "You must go to guru." And who is guru? This paramparā system. Evaṁ paramparā-prāptam imaṁ rājarṣayo viduḥ (BG 4.2).
So this is the process. If you want perfect knowledge, you must approach guru. And who is guru? Guru means the representative of the Supreme Personality of Godhead. Ācāryaṁ māṁ vijānīyān nāvamanyeta karhicit (SB 11.17.27). "Ācārya," Kṛṣṇa says, māṁ vijānīyāt: "he is Myself. I am. Because he is My perfect representative—he won't speak anything nonsense; he will speak something or everything which he has heard from Me—therefore he is ācārya." Ācārya means one who knows the śāstra and practically uses in his life, and the same thing, he teaches to his disciple. That is called ācārya. Ācārya is not a self-made man. No. Ācārya means ācinoti yaḥ śāstrāṇi. One who understand the śāstra, the Vedic śāstra, and practices in life and teaches the same thing to his student—that is called ācārya. So ācāryaṁ māṁ vijānīyān nāvamanyeta karhicit, na asūyeta martya-buddhyā (SB 11.17.27). So ācārya should not be considered as ordinary man, because he is representative of Kṛṣṇa. Sākṣād-dharitvena samasta-śāstraiḥ. Viśvanātha Cakravartī Ṭhākura says, "All the śāstras..." The śāstra is the basic strength, platform. So all the śāstra says the ācārya: "He is representative of the Supreme Lord." So sākṣād-dharitvena. Sākṣāt, not indirectly, supposingly. No. Directly, sākṣāt. Sākṣāt means directly. So how he is directly representative? Suppose Kṛṣṇa appeared five thousand years ago or millions of years ago, because Kṛṣṇa first spoke to Vivasvān. Imaṁ vivasvate yogaṁ proktavān aham avyayam: (BG 4.1) "This yoga system, I first of all explained to Vivasvān, the sun-god." That means millions and millions of years. Later on, again, He explained. So He says that "That very old thing, again I am explaining to you, Arjuna. There is no change."