Śyāmasundara: So he says that he wants to find some categories which define the characteristics of everything, that everything possesses these things in common.
Prabhupāda: That five elements: earth, water, fire, air... Anything you take, these things are there. And subtler things: mind, intelligence, and ego. As it is stated in the Bhagavad-gītā that these eight kinds of material elements are differentiated energy of Kṛṣṇa.
Śyāmasundara: His categories are a little more abstract. He says that the primary category is motion.
Prabhupāda: But wherefrom the motion comes? That is insufficient knowledge. When you... Motion means somebody must move, push on. That is accepted by Professor Einstein. If somebody has pushed, the motion has begun. Now it is going on. Just like in the billiard table, push one ball, "Hut!" And it goes.
Śyāmasundara: Yes. So he says that there are four major categories besides the primary category of motion and they are 1) identity or diversity. Each thing has a personal identity, an individuality, and each thing is different from every other thing.
Prabhupāda: Yes. That is called sajātīya-vijātīya bheda in Sanskrit. Different... Sajātīya. Just like two trees, two mango trees, but still there is difference. They are one as mango tree, but this tree is different from that tree. Similarly, the fingers. As finger they are one, but this finger is different from this finger. Although sajātī. Sajātī means of the same category, but there is difference. Although the same category, finger, but this finger is bigger than this finger. The whole body. It's a part of the body. Hand is different from leg. Leg is different from his head. Head is different from palm. Palm is different from sole. There are so many differences. They are called sajātī vijātī.