drastur lingatvam eva ca
tan-matratvam ca nabhaso
laksanam kavayo viduh
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Persons who are learned and who have true knowledge define sound as that which conveys the idea of an object, indicates the presence of a speaker screened from our view and constitutes the subtle form of ether.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
It is very clear herein that as soon as we speak of hearing, there must be a speaker; without a speaker there is no question of hearing. Therefore the Vedic knowledge, which is known as sruti, or that which is received by hearing, is also called apaurusa. Apaurusa means “not spoken by any person materially created.” It is stated in the beginning of Srimad-Bhagavatam, tene brahma hrda. The sound of Brahman, or Veda, was first impregnated into the heart of Brahma, the original learned man (adi-kavaye). How did he become learned? Whenever there is learning, there must be a speaker and the process of hearing. But Brahma was the first created being. Who spoke to him? Since no one was there, who was the spiritual master to give knowledge? He was the only living creature; therefore the Vedic knowledge was imparted within his heart by the Supreme Personality of Godhead, who is seated within everyone as Paramatma. Vedic knowledge is understood to be spoken by the Supreme Lord, and therefore it is free from the defects of material understanding. Material understanding is defective. If we hear something from a conditioned soul, it is full of defects. All material and mundane information is tainted by illusion, error, cheating and imperfection of the senses. Because Vedic knowledge was imparted by the Supreme Lord, who is transcendental to material creation, it is perfect. If we receive that Vedic knowledge from Brahma in disciplic succession, then we receive perfect knowledge.
Every word we hear has a meaning behind it. As soon as we hear the word “water,” there is a substance — water — behind the word. Similarly, as soon as we hear the word “God,” there is a meaning to it. If we receive that meaning and explanation of “God” from God Himself, then it is perfect. But if we speculate about the meaning of “God,” it is imperfect. Bhagavad-gita, which is the science of God, is spoken by the Personality of Godhead Himself. This is perfect knowledge. Mental speculators or so-called philosophers who are researching what is actually God will never understand the nature of God. The science of God has to be understood in disciplic succession from Brahma, who was first instructed about knowledge of God by God Himself. We can understand the knowledge of God by hearing Bhagavad-gita from a person authorized in the disciplic succession.
When we speak of seeing, there must be form. By our sense perception, the beginning experience is the sky. Sky is the beginning of form. And from the sky, other forms emanate. Therefore the objects of knowledge and sense perception begin from the sky.