Martin: ...who has the best brain?
Prabhupāda: That you can understand. Just like you are a scientist friend. You can do something which I cannot do. That much I must accept that you have got better brain. What is the difficulty?
Martin: But... How can I know?
Prabhupāda: You can know directly that "He is doing better than me." What is the difficulty? I can see... Just like all my disciples, they are following me. Why? Because they understand that "Our spiritual master explains about God better than us." Therefore they are surrendering. I am not bribing them. They are not fools. They have got very nice brain to act. So they accept me as the spiritual master brain because they understand it that "He can explain about God better than me." Where is the difficulty? These, all my disciples, surrenders unto me because they have found in me a better brain in explaining what is God. Direct perception. There is no question of indirect understanding. It is direct understanding. And the Vedas also advises that "Go to a better man," śrotriyaṁ brahma-niṣṭham (MU 1.2.12), "one who heard better and wise from the Vedic knowledge, and brahma, as a result of it he has become fully devoted to Kṛṣṇa," brahma-niṣṭham. These are the qualifications of spiritual master. His knowledge is perfect according to the Vedic injunction, and by having that knowledge he has become a perfect devotee of the Lord. These two things are to be seen. Then he is a spiritual master.
Martin: But there are many spiritual masters in the world. Each says...
Prabhupāda: Each says, but you have to judge. Just like when you go to purchase two shillings' worth goods, you go to different stores. Everyone says, "Oh, my thing is very nice." But you have to judge which one is best. That depends on you. If you are a fool, then somebody will cheat you. And if you are not a fool, then you will know... Just like these rascals, they call themselves God. Such a fool can cheat another fool only. But one who knows what is God, he'll not accept it. One who knows Kṛṣṇa, he'll not accept him as God. He'll immediately compare, "What you have done like Kṛṣṇa or better than Kṛṣṇa that I shall accept you God? We have already our God, Kṛṣṇa. Now you prove that you are better than Kṛṣṇa or equal to Kṛṣṇa." That he cannot, so why I shall accept him as God? Why shall I accept him as spiritual master? That depends on your intelligence. If you are less intelligent, then you'll be cheated by this false God. So everyone has got intelligence, individuality, power of understanding, so you should try to use them, and then you can understand.