Because we have no imagination, we have no instrument, neither we have sufficient knowledge what is the length and breadth of the form of the living entity, therefore Vedic literature gives you an idea that you just try to imagine one ten-thousandth part of the point, and that is the measurement. Keśāgra-śata-bhāgasya śatadhā kalpitasya ca, jīvo bhāgaḥ sa vijñeyaḥ sa cānantyāya kalpate (CC Madhya 19.140). So living entities, spiritual spark, that measurement is given there. Whenever there is measurement, there is form. It is not...
But because we cannot see the form, we say nirākāra. It is our incompetency. Just like I cannot see beyond this wall. My seeing power is limited. Therefore I see there is nothing beyond this. There is nothing beyond this room. That is not fact. There is everything. I can see the sun, which is fourteen hundred thousand times bigger than this planet, but my eyes are seeing, daily just like a disc. So don't believe your senses. Your senses are imperfect. Whatever knowledge you get by experimental knowledge, experimental method, that is the modern ways of understanding. But these things cannot be experimented. Therefore we have to take the knowledge from the Vedas.