While instructing Śrīla Rūpa Gosvāmī on the science of devotional service, Lord Caitanya discussed in some detail the material world and the living entities. He pointed out that among the 8,400,000 species of life—900,000 species of aquatics, 2,000,000 kinds of plants, 1,100,000 varieties of insects, 1,000,000 species of birds, 3,000,000 kinds of beasts, and 400,000 species of humans—Homo sapiens are clearly in the minority. Furthermore, humans are subdivided into three categories, namely, the uncivilized, the half-civilized, and the civilized. Also, many who supposedly belong to the civilized group act without restraint and discipline, only for the purpose of enjoyment. In this way they create chaos for the rest. Their sole intention in life being to gratify their senses (their instruments of enjoyment), they always try to keep their senses in fit working condition. They even go to the extent of transplanting monkeys' organs into their bodies once they get too old to enjoy with the vigor of youth.
Such gross sense enjoyers do not understand that the mind is more subtle than the sense organs and superior to them. Superior to the mind is the intelligence, and behind the intelligence is the false ego, which is far superior to the intelligence and which covers the spirit soul. Philosophical inquiry into the existence of the soul will remain a subject beyond the reach of these gross materialists. The gross sense enjoyers are actually to be counted among the animals, because man has more serious matters to attend to than just titillating his senses. Hence he is considered the most advanced among all the living entities. And indeed we do find that some men comprehend the gravity of human life. They carefully reject chaotic living, emulate the exemplary lives of saintly persons, and direct their lives in such a way as to fulfill the purpose of human life.
Followers of various religions—such as the Christians, Hindus, Muslims, and Buddhists—all adhere to the rules of their faith according to the intensity of their belief and the circumstances in their respective countries. Lord Kṛṣṇa speaks of these persons in Bhagavad-gītā (7.3):
- manuṣyāṇāṁ sahasreṣu
- kaścid yatati siddhaye
- yatatām api siddhānāṁ
- kaścin māṁ vetti tattvataḥ
Out of many thousands among men, one may endeavor for perfection, and of those who have achieved perfection, hardly one knows Me in Truth.