Perfect knowledge of Krishna removes all doubt and renders everything else superfluous through humble submission.Listen — Srila Prabhupada Uvaca
Bhagavad-gītā 7.1–3 — December 14, 1972, Ahmedabad 721214BG-AHMEDABAD [49:38 Minutes] Bg-07.01–03_721214BG-AHMEDABAD Prabhupāda: ...pārtha yogaṁ yuñjan mad-āśrayaḥ asaṁśayaṁ samagraṁ māṁ yathā jñāsyasi tac chṛṇu [Bg. 7.1] So Kṛṣṇa is advising simply by increasing your attachment for Kṛṣṇa, simply always being absorbed in the thought of Kṛṣṇa, we can be eligible to understand the whole knowledge, complete knowledge, without any doubt. By our mental speculation we acquire knowledge, but there are so many doubts. So many doubts. In the Ninth Chapter also, in the Bhagavad-gītā, it is said, pratyakṣa avagamaṁ dharmyam [Bg. 9.2].
Pratyakṣa. Kṛṣṇa consciousness knowledge is so perfect that pratyakṣa avagamam, you can directly perceive how far you are making progress. You don't require to take certificate from others, whether you are progressing or not. You'll understand yourself.
The example is given, just like a hungry man is eating, so as he going on eating, he's getting strength, and his hunger is being satisfied. So he can understand himself. Nobody requires to certify, "Now you are satisfied," or "Now..." Similarly bhakti, Kṛṣṇa consciousness, is so perfect that pratyakṣa avagamam, one can understand directly. Bhaktiḥ pareśānubhavo viraktir anyatra syāt [SB 11.2.42].
This is the test of bhakti-mārga. Therefore Kṛṣṇa says asaṁśayam. The theoretical knowledge, experimental knowledge, always remains in doubt. All the scientists, they are not confident.
Now there is a theory, "Theory of Uncertainty," among the scientists. Whatever knowledge they are making, they are making progress, everything is uncertain. Yes. It must be uncertain, because the basic principle is wrong.
Therefore it must be uncertain. A conditioned soul, as we are, under the condition of the material nature, three modes of material nature, how our knowledge can be perfect? It is not possible. The first defect is, because we are conditioned, we commit mistake, so many. And we become illusioned.
Just like every knowledge is being based on the illusion that "I am this body, material body," which I am not. But the whole world is going on under this conception that "I am this body." "I am American," "I am Indian," "I am brāhmaṇa," like that. So the basic principle is illusion. And there are so many mistakes we commit. And the senses are imperfect.