So we cannot estimate by direct perception even in this material world, and what to speak of the spiritual world. Not possible. Panthās tu koṭi-śata-vatsara-sampragamyo vāyor athāpi manaso muni-puṅgavānām (Bs. 5.34). By mental . . . muni-puṅga means mental speculation. You can go on mental speculating, but if you do even for many hundreds and thousand of years, it is not possible to calculate. You have to accept this truth through the śāstra—otherwise, it is not possible. Therefore Kṛṣṇa said, nityasyoktāḥ śarīr-ukta. Ukta means "It is said." Not that, "I am presenting some dogma," although He can do so; He's Supreme Personality of Godhead. This is the method. Unless there is ukta, said by authorities, previous authorities, ācāryas, you cannot say anything. This is called paramparā. You try to understand with your intelligence, but you cannot make any addition or alteration. That is not possible. Therefore it is called nityasyoktāḥ. It is said; it is already settled. You cannot argue. Nityasyoktāḥ śarīriṇaḥ anāśino 'prameyasya, immeasurable.
Now, this soul, as in the previous verse we have understood, avināśi tu tad viddhi yena sarvam idaṁ tatam (BG 2.17). This is not measurement of the soul, but the power of the soul you can measure. But not the soul. It is not possible. Soul is so small that it is not possible. You have no measuring means, and because now our material senses, it is not possible. You can simply understand by consciousness. Just like when Caitanya Mahāprabhu fainted in the Jagannātha temple, Sarvabhauma Bhaṭṭācārya examined that there was no consciousness. Even the abdomen was not moving.
When you actually you have consciousness and you breathe, the abdomen moves. But Caitanya Mahāprabhu's abdomen was tested by Sarvabhauma Bhaṭṭācārya. It was also not moving. So he thought that, "This sannyāsī might have died." But he again tried. He brought a little cotton swab and put before His nostril, and when he saw the swab, the fibers little moving, then he became hopeful, yes.
So everything has got a different type of calculation, measurement. But so far the soul is concerned, it is said here, aprameyasya: there is no source of measurement. There is no source. Therefore, the so-called materialist science, they say there is no soul. No, there is soul. This is the proof there is soul. This is the proof. What is that proof? First of all there is consciousness. This is the proof. But you cannot measure. The place is also located: the soul is there in the heart. Īśvaraḥ sarva-bhūtānāṁ hṛd-deśe 'rjuna tiṣṭhati (BG 18.61).
So the soul is in the heart and Kṛṣṇa is also in the heart, because they remain both together. So place is also located. You can perceive also by consciousness where there is presentation of soul, but if you want to measure by experiment, that is not possible. Therefore it is called aprameya. Prameya means direct perception: I can see or I can touch, I can handle. So that is . . . Kṛṣṇa says no, it is not possible. Aprameya. Then, how I shall accept? Now Kṛṣṇa says. So how I can believe Kṛṣṇa? Kṛṣṇa says ukta, it is already settled up by authorities. Ukta. This is paramparā system. Kṛṣṇa also says ukta. Kṛṣṇa does not say that, "I speak." No. Ukta, "there is Vedic evidence." Where it is? In the Upaniṣads there is. Just like:
- bālāgra-śata-bhāgasya
- śatadhā kalpitasya ca
- bhāgo jīvaḥ sa vijñeyaḥ
- sa cānantyāya kalpate
- (Śvetāśvatara Upaniṣad 5.9)
It is in the Upaniṣad, Śvetāśvatara Upaniṣad. This is called Vedic evidence.