So, na satyaṁ teṣu vidyate. The demonic people, they do not have the truth. Only on false theory, the Darwin's theory... We have commented upon Darwin's theory also in our book, Scientific Basis of Kṛṣṇa Consciousness. Dr. Svarūpa Dāmodara Brahmacārī, he has written a small booklet. He has criticized Darwin very strongly, that he is a speculator. A speculator cannot give you truth. That is not possible. By speculation you cannot say, "Two plus two equal to five." That is not science. "Two plus two equal to four," that is everywhere. And if you speculate, "No, two plus two equal to five," or "two plus two equal to three," that is not science. So scientific basis means it should be fact, not speculation, mano-dharma. Mano-dharma means speculation.
Therefore śāstra says, harāv abhaktasya kuto mahad-guṇā mano-rathenāsati dhāvato bahiḥ (SB 5.18.12). Harāv abhaktasya, one who is not a divine nature or devotee of the Lord, he has no qualification. "Oh, he's MA, PhD." No, he has no qualification. "Why?" Now, mano-rathena, he is simply speculating. He has no truth. How by speculation...? Every one of us, we are imperfect. We are very much proud of our eyes: "Can you show me?" What qualification your eyes have got that you can see? He does not think that, that "I have no qualification; still, I want to see." These eyes, oh, they are dependent on so many condition. Now there is electricity, you can see. As soon as there is electricity off, you cannot see. Then what is the value of your eyes? You cannot see what is going on beyond this wall.
So don't believe your so-called senses as the source of knowledge. No. The source of knowledge should be by hearing. That is called śruti. Therefore Vedas' name is śruti. Śruti-pramāṇa, śruti-pramāṇa. Just like a child or a boy wants to know who is his father. So what is the evidence? That evidence is śruti, hearing from the mother. Mother says, "He is your father." So he hears; he does not see how he became his father. Because before his body was constructed the father was there, how could he see? So by seeing, you cannot ascertain who is your father. You have to hear from the authority. The mother is the authority. Therefore śruti-pramāṇa: the evidence is hearing, not by seeing. Seeing... Our imperfect eyes... There are so many obstacles. So similarly, by direct perception, you cannot have the truth.
Direct perception is speculation. Dr. Frog. Dr. Frog is speculating what is Atlantic Ocean. He is in the well, three feet well, and some friend inform him, "Oh, I have seen vast water." "What is that vast water?" "Atlantic Ocean." "How big it is?" "Very, very big." So the Dr. Frog is thinking, "Maybe four feet. This well is three feet. It may be four feet. All right, five feet. Come on, ten feet." So in this way, speculating, how the frog, Dr. Frog, will understand Atlantic Ocean or Pacific Ocean? Can you estimate the length and breadth of the Atlantic, Pacific Ocean, by speculation? So by speculation, you cannot have. They are speculating so many years about this universe, how many stars are there, what is the length and breadth, where is the... Nobody knows anything even of the material world, and what to speak of the spiritual world? That is beyond, far beyond.
Paras tasmāt tu bhāvo 'nyo 'vyakto 'vyaktāt sanātanaḥ (BG 8.20). You'll find in the Bhagavad-gītā. There is another nature. This nature, what you see, the sky, a round dome, that, above that, there are layers of five elements again. This is the covering. Just like you have seen the coconut. There is hard covering, and within the covering there is water. Similarly, within this covering... And outside the covering there are five layers, thousand times bigger than the one another: Water layer, air layer, fire layer. So you have to penetrate all these layers. Then you will get the spiritual world. All these universes, unlimited number, koṭi. Yasya prabhā prabhavato jagad-aṇḍa-koṭi (Bs. 5.40). Jagad-aṇḍa means the universe. Koṭi, many millions clustered together, that is material world. And beyond that material world there is spiritual world, another sky. That is also sky. That is called paravyoma. So by your sense perception you cannot estimate even what is there in the moon planet or sun planet, this planet, within this universe. How you can understand the spiritual world by speculation? This is foolishness.