From ancient times, Man has searched for answers to the question, "What am I?" Human beings, even in their primitive stage, are never satisfied with their Biological needs alone, like animals. They wanted to know what his true nature was and what the aim and purpose of his life were. The Being, in whatever form he is conceived as, is, nevertheless, a complex being who can evolve into a psychological being. Another important aspect of Humanity is that humans are social and moral beings; at times, they sacrifice their egoistic impulses for the sake of society. As a religious person, he seeks support from a greater Being, such as God, in his life. Again, he can be said to be a spiritual being when he realizes that, eventually, all Humanity and even all creatures will be made the objects of compassion because all of them are equally subjected to various types of pain and psychological grief. However, there exists after death, and that is his soul or spirit. Thus, Man is endowed with complexities by material, psychological, social, and moral being at a time. In this paper I would like to draw and sketch the fundamental nature of man according to Rabindranath Tagore, and how to apply in it our lives.