The first sloka in the Yaksha Prasna has four questions and is followed by Yudhishtira’s succinct reply to all these. To the first question, “Who is it who makes Aditya or the sun to rise?”, the answer given is that the Vedas help Aditya to rise. Neelakanta in his commentary says that Yudhishtira thinks of the atma or the soul of man when sun is mentioned. So it means the soul which through the five senses, mind and intellect gains knowledge of the world
