Krishna can change anything, therefore we worship Him as the greatest Scientist. If a man knows swimming he can stay up. So if a man has this much power, what to speak of God. So we see that Ramacandra has the art how to make stones float. It is a question of knowing the art. Art means the display of intellectual energy. Everywhere we can see intelligence in everything, so the Lord knows the art of everything, so He can change anything, we cannot.
Letter to Rupanuga, May 3, 1972