As I have learned more about the study of literature, I have realized that there are many ways of looking at works of literature. For the last twenty years or so, the theory-based approach has prevailed. Scholars pick a topic, such as deconstruction, or politics, or gender issues, or psychology, or reader-response, or philosophy. Then, they only look at how the literature relates to that external or discipline.
This theory-based approach is useful. However, it allows us to be sloppy in two ways. First, by creating a list of external categories with which we can connect a poem, we can begin to see in literature what may not be there. Second, we risk the danger of substituting the task of comparison for the act of truly understanding. Such a theory-based approach makes us feel good. It can make us feel like we know something special about the poem that may not be obvious within the poem.
A theory-based approach may also, when combined with the need to publish, slip into the cult of the academic trend-du-jour.