An interesting story has been described by our Satsvarūpa Mahārāja in the Back to Godhead: The learned scholar and the boatman. The boatman... In Bengal there are many rivers, and so people generally transport by boat service. So a learned scholar from Calcutta, say, was going home in the village on a boat, and he was very happy. So he was asking the boatman, "My dear boatman, do you know what are these stars, this astronomy, how they are working?" "No, sir, I do not know." "Oh, your life is twenty-five percent lost. You do not know anything." Then after some time, "You know the geology, how this earth, water, they are working?" "No, sir, I am poor man. What can I know?" "Oh, your fifty percent of your life is lost." Then all of a sudden there was a cloud, black cloud on the sky, and there was storm. Then at that time the boatman asked, "Sir, do you know how to swim?" "No, I do not know." "Then one hundred percent you have lost.(laughter) You are going to be drowned." He jumped and he drowned. So this is the point. So you are trying to understand the whole analytical study of the material world. That is very good. But if you do not know how to remember Nārāyaṇa at the time of death, then you are going to be cats and dogs. That's all.You can listen this story from here, read & listen more story from Prabhupada from here.