Lord Kṛṣṇa says that "The four divisions of social order is made by Me." How? Guṇa-karma-vibhāgaśaḥ: by division of quality and work. Not that because one is born in a brāhmaṇa family, as it is going on in India. No. In the śāstra there is no such thing, janma-karma-vibhāgaśaḥ. No. Guṇa-karma-vibhāgaśaḥ.
In the Bhagavad-gītā Kṛṣṇa personally says, guṇa-karma-vibhāgaśaḥ. One must have the brahminical qualifications: truthful, clean, sattva, śauca. Sama—controlling the mind; damaḥ—controlling the senses; sattva śauca sama damah, titikṣā—tolerance; ārjava—simplicity; jñānaṁ—full knowledge; vijñānaṁ—practical application in life; jñānaṁ, āstikyaṁ—and full faith in Vedas, that is called āstikyaṁ. This is brahma-karma svabhāva-jam.
So the highest perfection of human life is to attain the brahminical qualification, then everything will be clearly understood: what is God, what I am, what is my relationship with God, what is this world. So many questions. But they are not interested. At the present moment people are not interested in these things, na te viduḥ svārtha-gatiṁ hi viṣṇuṁ. They are interested in animal propensities: how to eat nicely, how to sleep nicely, how to defend nicely, āhāra, nidrā, bhaya, and how to have sex life nicely. That's all.
But this is not the occupation of the human life; this is animal life. Simply to be busy with these four principles of life, āhāra, nidrā, bhaya, maithuna, that is animal propensities. A man has to go beyond that. Of course, so long we have got this body, the animal propensities will remain there, because the human being is defined in logic; a man is rationalist. I think this is not the proper definition. Rationality there is in animals also. The śāstric definition, dharma, dharmeṇa hīnāḥ paśubhiḥ samānāḥ (Hitopadeśa). Therefore in every human society there is a certain type of religion, faith, and the purpose of religion is to understand Viṣṇu, Kṛṣṇa, the Supreme Lord.
So actually, at the present moment... Not only the present moment; this is the nature. People forget their relationship with Viṣṇu, or Kṛṣṇa, and they therefore drag on this material existence. Dragging on material existence means repeatedly take birth and death, and in different species of life. Not that after death there is any guarantee that we shall get human form of life. There is no guarantee. Any form. There are 8,400,000 species of life forms. We can get any form according to our work.