Paras tasmāt tu bhāvo 'nyo 'vyakto 'vyaktāt sanātanaḥ (BG 8.20), you'll find in the Bhagavad-gītā. There is another nature. This nature, what you see, the sky, a round dome, this, that, above that, there are layers of five elements again. This is the covering. Just like you have seen the coconut. There is hard covering, and within the covering there is water. Similarly, within this covering . . . and outside the covering there are five layers, thousand times bigger than the one another: water layer, air layer, fire layer. So you have to penetrate all these layers. Then you will get the spiritual world. All these universes, unlimited number, koṭi. Yasya prabhā prabhavato jagad-aṇḍa-koṭi (Bs. 5.40). Jagad-aṇḍa means the universe. Koṭi, many millions clustered together, that is material world. And beyond that material world there is spiritual world, another sky. That is also sky. That is called paravyoma. So by your sense perception you cannot estimate even what is there in the moon planet or sun planet, this planet, within this universe. How you can understand the spiritual world by speculation? This is foolishness.
Therefore śāstra says, acintyāḥ khalu ye bhāvā na tāṁs tarkeṇa yojayet (Skanda Purāṇa). Acintya, which is inconceivable, beyond your sense perception, don't try to argue and understand it and speculate. This is foolishness. It is not possible. Therefore we have to go to the guru. Tad-vijñānārthaṁ sa gurum evābhigacchet, samit-pāṇiḥ śrotriyaṁ brahma-niṣṭham (MU 1.2.12). This is the process. But the demons, they do not know this is the process. They speculate; they manufacture. Simply by jugglery of words they manufacture their truth. No. Satyaṁ paraṁ dhīmahi. That is in the Bhāgavatam, you'll find. And what is satyam? Janmādy asya yato 'nvayād itarataś cārtheṣv abhijñaḥ svarāṭ tene brahma hṛdā . . . (SB 1.1.1). Everything is there.