This Bhāgavata-grantha, śāstra, was written five thousand years ago. Now five thousand years ago there was no Buddha. But in future he will come, and that is mentioned here: bhaviṣyati. Not only Buddha's name only, but his mother's name and the place where he would appear. This is called śāstra. No speculation. Fact. Either past, present or future, it doesn't matter. Tri-kāla-jña.
So we accept knowledge from such person who knows past, present and future. Persons who do not know even present what is going on, how we can accept knowledge from him? This is not our process. Our process is to receive knowledge from a person who knows past, present and future. Just like Kṛṣṇa and the ācāryas. They know. So our knowledge is perfect because we are receiving knowledge from the perfect, as it is. Therefore our knowledge . . . it is not that I am perfect. I may not be perfect, I may be perfect. But because I am accepting the perfect knowledge, therefore whatever I speak on that basis, that is perfect. This is our process.
You don't require to research. What research you will make? You are yourself insufficient. What research you can make? Your senses are insufficient. You try to see the cosmic manifestation with your microscope or telescope, but that is also manufactured by you. You are imperfect, so whatever you have done, that is all imperfect. How you can know?