The poem discusses the purpose and meaning of life. It argues that life is real and not empty like a dream. People should act in the present and not dwell on the past or future. The purpose of life is self-improvement and action, not just experiencing joy or sorrow. People should follow the example of great men and make their own mark instead of passively following others. The overall message is to face life's challenges bravely and continue striving to better oneself.