Only a sadhu can recognise a sadhu. An asadhu cannot recognise a sadhu. In the same manner, an illiterate person cannot understand a learned person because he does not have the capacity to understand. Only a learned person can offer his respects to another learned person. A sadhu can recognise other sadhus. Non-sadhus cannot. For example, Sukadeva Gosvami, the son of Vedavyasa Muni, was a great saint. He was a brahma-jnani even when he was in his mother's womb. After his birth he left immediately for the forest. His father was crying, "Oh son, oh son!" He was a great jnani, a great yogi and a suddha-bhakta. The suddha-bhaktas, yogis and jnanis all used to give respect to Sukadeva Gosvami. When Sukadeva Gosvami was sixteen years of age, he walked through different villages naked, because he had no connection with this world (brahma-jnani). The villagers thought that he was a crazy person, a lunatic. They would throw dirt at him and spit on him. As he had no connection with this world, he would not say anything. These villagers could not understand him. He set his holy footprints at Sukartala by the bank of the Ganges and Pariksit Maharaja came to see him after having been cursed by a brahmana. Pariksit Maharaja was destined to die from snakebite after seven days. Renouncing his home and kingdom, Pariksit came to Sukartäla by the side of the Ganges River. I had the opportunity to go there two or three times with our Guru Maharaja. It is still now a calm and serene place. When Sukadeva Gosvami set his holy footprints there, all the rsis came to see him. Narada Muni, Parasurama and many other great saints were there. They all stood up with great reverence and offered their obeisances to Sukadeva Gosvami because they could understand his qualification. As Sukadeva Gosvami started speaking Srimad-Bhagavatam, they were astounded that this boy had so much learning. You cannot understand a learned person by observing his outward appearance. But when you hear him, you can understand that he is very learned. By hearing you can understand, not by seeing with your eyes.