A suitable metaphor (=an really apt metaphor) The metaphor of building on sand is relevant given the task we confront. A main metaphor (one that a poem or book is based around) A major metaphor in the book is the poet as something dragged by the sea. The phrase "dragged along by the sea" is one of many metaphors used to describe the experience of being a poet. An apt metaphor is a good one; it makes an abstract concept more accessible to readers by linking it to something they understand better. For example, when William Blake wrote that imagination is the ladder by which man reaches heaven, he was using his poetic license to explain what imagination is. But since everyone knows what heaven is and how it can be reached through prayer, religion, and virtue, nobody questioned the accuracy of the image until science began to evolve about 250 years later. At that point, some philosophers concluded that heaven cannot actually be reached by human means because brain function is too complex for us to control directly. However, imagination remains important today because it helps us transcend our physical limitations by allowing us to see possibilities beyond those presented by reality. Heaven's doorway is always open, but you have to be able to walk through it to reach it. Since humans can't physically go anywhere except through time, imagination allows us to move forward even though we are stuck in place.