This science of Bhagavad-gītā has to be accepted by disciplic succession. That is the way of accepting any scientific thing. Just like even in material science, suppose if you have to become a medical practitioner or a lawyer.
So you have to study the law books by the previous lawyers, by the judgments of the courts. One who has studied the previous records of legal implications, he is best lawyer. Similarly, a medical practicer, practitioner, who has studied the previous books and knowledge and experience, he is called experienced physician.
The same principle is there that the spiritual knowl . . . you cannot manufacture any spiritual knowledge. That is atheism. You cannot manufacture any religious principle. It is not possible. That is not accepted in Vedas. Dharmaṁ tu sākṣād bhagavat-praṇī (SB 6.3.19). Dharma means the rules and regulation which is given by God. That is accepted everywhere. In Bible, in Koran also. The laws of God. You cannot manufacture. So Kṛṣṇa said that this principle of Bhagavad-gītā . . . at the present moment Bhagavad-gītā is being interpreted by anyone and everyone according to his whims.
That is not permissible. That is not Bhagavad-gītā. We have to understand this. Simply Bhagavad-gītā is that which is received by the paramparā system. That is being explained.