Darśinaḥ means who has actually seen.
Dr. Patel: They are explaining the truth in their own way. That is the change of theory. But the truth is the same.
Prabhupāda: That is the truth of rascaldom, as soon as you change your position.
Dr. Patel: Theory is rascal, but the truth is never rascal.
Prabhupāda: No, no, truth you do not know. Therefore rascaldom.
Dr. Patel: They do not know how to explain. Truth is there, sir.
Prabhupāda: No, no. Anyway, he does not know. Therefore he is a rascal, either you say this way or that way.
Dr. Patel: Truth is there.
Prabhupāda: No, no, truth is there, but they cannot present the truth rightly. That is rascaldom. Truth is there; that is certain. But they cannot present the truth in right way.
Dr. Patel: You mean they are groping in the dark.
Prabhupāda: Yes. That is rascal. How things are happening—every ten years they are changing their theory. And that has been explained by, not by a layman like me. The Dr. Svarūpa Dāmodara, he has explained. He has concluded Darwin's theory completely wrong. You have read that small booklet?
Dr. Patel: Yes.
Prabhupāda: And he has given reason, quotation, how simply he's speculator.
Dr. Patel: As a matter of, sir, the whole cosmos is full of, I mean, intelligence. That is God. But then that intelligence is struck in different way to the, what you call the mind, which is embedded in the matter. So, I mean, each one explains it in his own way, as he understands...
Prabhupāda: No, no. You cannot explain truth in your own way.
Dr. Patel: The whole truth nobody knows and sees. Even our śāstra says.
Prabhupāda: Hare Kṛṣṇa. Things which one does not know, he should not try to cheat others by placing some untruth.
Dr. Patel: It is like five blind men seeing an elephant.
Prabhupāda: Yes. So you should not give the conclusion that "Elephant is like..."
Dr. Patel: Then we don't accept... It is very difficult to know the whole truth by any one of us.
Prabhupāda: No. Therefore our process is upadekṣyanti tad jñānaṁ jñāninas tattva-darśinaḥ. One has seen the truth. Not these rascals. Tattva-darśinaḥ. Darśinaḥ means who has actually seen. There is no change. The advice is tad viddhi praṇipātena paripraśnena sevaya (BG 4.34). These are the quotes. Upadekṣyanti tad jñānaṁ jñāninas tattva-darśinaḥ. Not that theoretical. Tattva-darśinaḥ. You have to go there. Then you will get knowledge. A blind man goes to another blind man. What is the profit? No profit.
Dr. Patel: Andhena andha-niyataḥ.(?)
Prabhupāda: Ah. Andha yathāndhair upanīyamānāḥ (SB 7.5.31). A blind man must go to a man who has got eyes, who has seen. Then that is right knowledge. Now we are presenting this book, Scientific Basis of Kṛṣṇa Consciousness. Let anyone come and challenge. Let anyone come. We have got many scientists. They will talk. What is the value of speculation?