Just like, practical. The geometrical calculation is that the sun, the dimension of the sun is many, many hundred, thousands of . . . greater than the earth. But we are seeing just like a disk. So our sense is unable to see how great it is. It is a material thing. So how we can see the greatness of God with these material eyes? It is not possible. As you are understanding about the sun by authoritative statement of the geometry, that this sun globe is so great, so many hundred thousands greater than the . . . but you are seeing just like a disk. So how to get the knowledge of the sun? By receiving through the ear. That's all. Simply you have to receive the knowledge from the authority. It is not that practically you are experimenting by going to the sun, that it is so great and so long, so broad. That is not possible. You have to receive such knowledge through authority. That's all.
So even for material understanding which is beyond our sense perception we have to receive knowledge from authority. Similarly, we cannot understand what is God. But from the authoritative sources we can understand that God is so great. Just like in the Brahma-saṁhitā it is stated that yasyaika-niśvasita-kālam athāvalambya jīvanti loma-vilajā jagad-aṇḍa-nāthāḥ (BS 5.30)—that you see this universe, and in each universe there is a predominating demigod which is called Brahmā, or jagad-aṇḍa-nātha, the master of the universe. That master of the universe is living, only taking the duration of breathing of Mahā-Viṣṇu. Just like you are breathing, inhaling and exhaling. So when Mahā-Viṣṇu exhales, innumerable universes come out. And when He inhales, all these universes go into His body. So just imagine how great He is, how big He is. That is not conceivable with our limited sense. But if we believe, then you get the perfect knowledge. There is no doubt. If you don't believe, there is no other way. You cannot understand what is God, or what is His length, what is His breadth.
So whenever in the scripture it is said that God is without form, that means He has no form which we have got experience. But He has got form. Just the same example. When you cannot measure, you say a point has no length, no breadth. But actually, it is not a fact. The point has length and breadth. We have no instrument to measure it, that's all. Similarly, when as soon as we say "form," we understand this form. Just like I am seeing your form, you are seeing my form. So we understand that God may be a form, and because God also comes in this form also. Just like in Bhagavad-gītā it is said, avajānanti māṁ mūḍhā mānuṣīṁ tanum āśritam: (BG 9.11) "Because I have come in the form of a(an) ordinary human being, they are deriding: 'How He can be God?' " So many scholars, so many philosophers, they deny to accept Kṛṣṇa, God. Why? Because He appears to be just like you and me, a human being. But God can appear in any way because He is all-powerful. He sometimes appears as fish; sometimes He appears as tortoise; sometimes He appears like a boar; sometimes He appears half-lion, half-man. Similarly sometimes He appears man, sometimes He appears as woman.