The sun, the most powerful planet within this universe, the eyes of the universe . . . yac-cakṣur eṣa savitā sakala-grahānām. Without sunrise, however expert you may be in science, you cannot see even. Therefore real eye—the sun. Any sane man will admit. Now it is darkness at night. Have any scientists any instrument to show that everything is visible? No. That is not possible. The real eyes. This is subsequent, secondary eyes. We are very much proud of our eyes, that "Can you show me God?" Are you able to see God? What is the value of your eyes? As soon as there is darkness, your eyes are finished. And you are so much proud, oh. Therefore Vedic injunction—śāstra-cakṣuṣa: "You must be seeing everything through the śāstra, not with your these rascal eyes." It has no value. Śāstra-cakṣuṣa. Tasmād śāstra-vidhān uktam, Kṛṣṇa said. Yaḥ śāstra-vidhim utsṛjya. The direction is the śāstra. You should see through the śāstra what is what. Then you'll be benefited. If you simply believe on your senses . . . the whole world, philosophers, scientists, they are going on on their own imperfect senses. Therefore everything is rascaldom. It is imperfect. It is not real knowledge. Śāstra-cakṣuṣa. You should know things through the śāstra guru. Sādhu-śāstra-guru-vākya, tinete kariyā aikya. This is . . . if you want to know something, then it must be confirmed by sādhu, śāstra and guru. Then it is complete. And if you speculate, if you establish something under speculation, then it is not right, it is wrong.
Therefore Kṛṣṇa, when He appeared on this planet, He, last instruction was that sarva-dharmān parityajya mām ekaṁ śaraṇaṁ (BG 18.66): "You just surrender to Me, and after giving up all your mental speculation, so-called religious system . . ." This is real religious system. So He left behind Him the Bhagavad-gītā to open our eyes, but we did not take much care of it. Therefore five hundred years ago Lord Caitanya appeared. He is Kṛṣṇa. He practically taught how to accept instruction of Kṛṣṇa.