As you can perceive here, within yourself, what is matter and what is spirit, similarly, there is spiritual world also. The two natures are there, as you can experience two natures here—the material nature and spiritual nature. This we have discussed in the Seventh Chapter of Śrīmad-Bhāgavata, er, Bhagavad-gītā. The spiritual nature is called superior nature, and this material nature is called inferior nature. So this material nature, beyond this material nature, there is spirit . . . superior nature, spiritual nature. This information we have got.
Now, it is not possible to understand this, these things, by experimental knowledge. Just like although you are seeing by microscope and other instrument, astronomical instruments, there are millions and millions of stars—actually you are seeing—but you cannot approach. Your senses, your means, are so insufficient that you cannot approach. What to speak of other planets, you cannot approach even the moon planet, which is the nearest. So just try to understand how much incapable you are.
So being incapable, don't try to understand God and God's kingdom by experimental knowledge. This is foolishness. It is not possible. You have to understand by hearing Bhagavad-gītā. And there is no other way. Just the same example: you cannot understand who is your father by experimental knowledge. You have to simply believe your mother. Similarly, you have to believe this Bhagavad-gītā. Then you can get all this information. There is no possibility of experimental knowledge. But if you become advanced in Kṛṣṇa consciousness, you'll realize. You'll realize.