Midway through the poem , there is a split between the two actions of the poem : the first attempts to identify with the nightingale and its song , and the second discuss the convergence of the past with the future while experiencing the present . This second theme is reminiscent of Keats 's view of human progression through the Mansion of Many Apartments and how man develop from experiencing and wanting only pleasure to understanding truth as a mixture of both pleasure and pain . The Elysian fields and the nightingale 's song in the first half of the poem represent the pleasurable moments that overwhelm the individual like a drug . However , the experience do not last forever , and the body is left desiring it until the narrator feel helpless without the pleasure . Instead of embracing the coming truth , the narrator clings to poetry to hide from the loss of pleasure . Poetry do not bring about the pleasure that the narrator original ask for , but it do liberate him from his desire for only pleasure .