In plain words
But the Ātma has one form, not these three,” Gārgī broke in. Then he explained. Black, white and red: these are the natural qualities of fire. These three are not separate. Fire appears red. It takes on a white form. When it goes out, it takes on a black form. Black is the mark of night. Red is the mark of dawn. White is the mark of day. The sun that is in these three is one alone. In the same way the Ātma, which is one, takes on many forms at many times. That is why no one at all has the right to settle anything about the Ātma as this or that, he thundered.
But Gārgī was not satisfied with this, and put another question: how many kinds of human beings are there in this world? There are four kinds of human beings in this world, he said. One, the human god. Two. The human man. Three. The human daitya. Four. The human beast. He laid it down that these four kinds of human beings are in this world. The man who knows Brahman is God. He who is joined with Satya and Dharma is a human being, he said. He who lives in the knowledge of Brahman, ever contemplating the thought of Brahman alone, seeing Brahman alone everywhere, and spends his time with no selfishness and no self-interest, is the man who knows Brahman. To recognise the truth that the divinity in all is one, to cast aside names and forms, and to experience only the eternal Consciousness: that nature is the knowing of Brahman. He who experiences humanness through such conduct, they called the divinity in man.
The humanness of man. He who makes his time holy by Satya and by Dharma, carries out the duties that are his, gives in charity, lives a life of equality with his fellow men, harms no one, hurts no one, loves all, and practises these human values, Satya and Dharma, on the eternal path every moment without forgetting them: he is the true human being.
He who drinks liquor, forgets his true mind and is lost in it, drunk, crazed, abusing others with whatever comes to his mouth, hurting others, tormenting them, and takes his own selfishness for life itself: he is the human daitya.
He who spends his life in food, sleep, fear and sex alone, takes food and drink to be his chief aims, enters into none of the matters of the world, is void of discriminating knowledge, gives not the least thought to such things as charity, cannot recognise what the path of Satya is, and lives like the beasts with only the pleasures and riches of his body in view: he is the human beast, he said.