If they do not believe in Ramayana, Mahabharata, Bhagavad-gita, then they are called unbelievers, so how can you believe their words. Then we come to the platform of reason and argument. If they do not believe in Ramayana and Mahabharata, then we shall reply point to point by argument and reason. Of course, it is not possible to come to the right conclusion simply by argument and reason, tarkanratishtanat.
Letter to Niranjana, 21 May, 1973