Prabhupāda: Yes. I was student of psychology. Our professor, Dr. Urquhart said that the brain, the biggest brain is, by practical psychology it has been tested, sixty-four ounce. And that is the highest brain substance. But for woman it is never more than thirty-six ounce. So they have tested all these practical psychologies.
So here the same word is used, that alpa-medhasa. It is very technical. Alpa means "very little" brain substance. Those who have got very little brain substance, they try like this. Kāṅkṣantaḥ karmaṇāṁ siddhiṁ yajanta iha devatāḥ. "Why little brain substance? He's getting profit from the demigods." Then brain substance little means he does not know what is his actual aim of life. He does not know. Na te viduḥ svārtha-gatiṁ hi viṣṇum (SB 7.5.31). Those who are trying to be happy within this material world, worshiping different types of demigods and taking benefit very soon, but he, because his brain substance is very little, he does not consider it that "How long I shall enjoy it? How long I shall enjoy?"
Kṛṣṇa says in the Bhagavad-gītā, ābrahma-bhuvanāl lokāḥ punar āvartino 'rjuna (BG 8.16). Even if you, by activities, pious activities, or worshiping different demigods, you go to the Brahmaloka, where the standard of life is very, very great, life is also, duration of life is very, very great, so that is not permanent. But our problem is that we are permanent, eternal, and we are trying to be happy in the nonpermanent condition of life. This is called less brain. My problem is that I am the spirit soul... Nityaḥ śāśvataḥ. I am eternal, śāśvataḥ. Na hanyate hanyamāne śarīre (BG 2.20). I do not die even after the annihilation of this body. Then where is my eternal body? This question should be raised by the human form of life.