This speech is part of Act 2, Scene 7 of William Shakespeare's play, As You Like It. It is neither a poem nor a song but an extended speech by the character Jaques who is expressing his usual melancholy at the expense of the human race. The cycle of life from the infant to the invalid old man resembling an infant, progressing through seven distinct stages is the theme of his speech. He starts by picking up on something the Duke has said and reflects, "All the world's a stage, and all the men and women merely players. They have their entrances and their exits . . ." Thus what he is saying is that everyone is an actor, acting all the time, just playing out caricatures of humanity.
He is not only saying that we are all playing in a play, but that it is a particularly badly written play at that. The characters we play are just corny stereotypes.
